Re: Python XML and tables using math
flebber, 16.08.2010 05:30: I am looking at a project that will import and modify an XML file and then export it to a table. Currently a flat file table system should be fine. I want to export the modified data to the table and then perform a handful of maths(largely simple statistical functions) to the data and then print out the resultant modified tables. I was planning on using Python 2.7 for the project. Has anyone used a guide to acheive something similar? I would like to read up on it so I can assess my options and best methods, any hints or tips? That can usually be done in a couple of lines in Python. The approach I keep recommending is to use cElementTree (in the stdlib), potentially its iterparse() function if the file is too large to easily fit into memory, but the code won't change much either way. You might want to skip through this list a bit, similar questions have been coming up every couple of weeks. The responses often include mostly complete implementations that you can borrow from. Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: Python why questions
in 639663 20100815 120123 Lawrence D'Oliveiro l...@geek-central.gen.new_zealand wrote: In message mailman.2084.1281741048.1673.python-l...@python.org, Ian Kelly wrote: The ability to change the minimum index is evil. Pascal allowed you to do that. And nobody ever characterized Pascal as âevilâ. Not for that reason, anyway... Why do you refer to Pascal in the past tense? I use it most days (Delphi Free Pascal). -- http://mail.python.org/mailman/listinfo/python-list
errors and exception
Hello, I am using things like: except Exception as inst: and with open(myfile.txt) as f: for line in f: print line Things that seems to be new in python 2.6 and higher, however reading http://docs.python.org/tutorial/errors.html and this not clear when this new syntaxes appeared. My trouble is that I want to make something similar above compatible with python 2.5, but when running python2.5 I got: except Exception as msg: ^ SyntaxError: invalid syntax If there's a way (e.g. from __future__ ..., inherited modified Exception class, etc) that could give a solution to keep my code in python 2.6 syntax as above but compatible with python 2.5, that would be appreciated. Many thanks in advance, Alan -- Alan Wilter S. da Silva, D.Sc. - CCPN Research Associate Department of Biochemistry, University of Cambridge. 80 Tennis Court Road, Cambridge CB2 1GA, UK. http://www.bio.cam.ac.uk/~awd28 -- http://mail.python.org/mailman/listinfo/python-list
Re: Working with PDFs?
jyoun...@kc.rr.com wrote: Just curious if anyone knows if it's possible to work with pdf documents with Python? I'd like to do the following: - Pull out text from each PDF page (to search for specific words) - Combine separate pdf documents into one document - Add bookmarks (with destination settings) A few programs I've been looking at are pdfminer, pyPDF, etc from this link: http://pypi.python.org/pypi?%3Aaction=searchterm=pdfsubmit=search Originally, I was using AppleScript and JavaScript to do this in Acrobat. But now Acrobat 9 has broken this process and I can't seem to make it work. I'd like to find other workarounds instead of having to rely on Adobe. Have you tried OpenOffice? -- http://mail.python.org/mailman/listinfo/python-list
Re: segfault with small pyqt script
Hi Hans-Peter, It seems, that my other posts did not get through. On 08/15/2010 11:17 PM, Hans-Peter Jansen wrote: For a starter, tell us the versions of python-sip, and python-qt4 or however they're called in Ubuntu. For the record, python-sip-4.10.5-1.1 python-qt4-4.7.4-1.1 doesn't show this behavior. Pete The problem seems to be known for 4.7.2. For simple code I managed to work around the issue. For the real more complicated I didn't. So it seems I'll have to avoid 4.7.2. Please see below: On 08/13/2010 09:11 AM, Gelonida wrote: Lee, On 08/13/2010 12:53 AM, Lee Harr wrote: I'm desperate. I'm having a real application, which fails rather often when finishing it. I'm not sure, whether any serious problem could be hidden behind it The script is a pyqt script, which segfaults most of the time on my ubuntu 10.4 linux 64 bit and I'm having trouble to understand why. Looks to be a known issue: http://www.google.com/search?q=pyqt+segfault+on+exit https://launchpad.net/bugs/561303 The last activity on that bug is almost 2 months ago... Hopefully the fix will be distributed soon. This seems to be the problem. In my case I can workaround the issue by adding one line. if __name__ == __main__: app = QApplication([]) myform = MyForm() myform.show() retcode = app.exec_() myform = None # THIS IS THE WORK AROUND print last For more complex multi widget examples it doesn't seem enough to just destroy the main widget. probably I had to recursively assign all widgets / dialogues sub widgets to None. So I'll just try to stay away from this pyqt release and stick with older or newer ones. -- http://mail.python.org/mailman/listinfo/python-list
[Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
[Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? Because a stack has push and pop, it is able to release and allocate memory. We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. The algorithm using the stack would have to be perfect to prevent stack overflow or condition of infinite recursion depth. This would involve data type checking to filter out invalid input. The task must be casted in an algorithm that uses the stack. Then the algorithm must be shown to be heuristically or by its metaphor, to be correct using informal reasoning. Are there any standard textbooks or papers that show stacks implemented in C/C++/Python/Forth with malloc/free in push and pop ? If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. KR ANSI has the example of modular programming showing how to implement a stack but he uses a fixed length array. It is also possibly an endogenous stack. We look for an exogenous stack so that element size can vary. === Standish P stnd...@gmail.com -- http://mail.python.org/mailman/listinfo/python-list
Re: errors and exception
On 08/16/2010 12:06 AM, Alan wrote: Hello, I am using things like: except Exception as inst: and The old syntax for exceptions still works in Python2.x (all versions). The new syntax works in Python2.6+ and Python3. try: whatever except Exception,msg: # Old syntax print msg with open(myfile.txt) as f: for line in f: print line You don't need the new fangled with statement if you want to be compatible with older versions of Python2. (It's nice and convenient, but not necessary.) f = open(myfile.txt) for line in f: print line f.close() # This is what the with statement guarantees; so now just do it yourself Gary Herron Things that seems to be new in python 2.6 and higher, however reading http://docs.python.org/tutorial/errors.html and this not clear when this new syntaxes appeared. My trouble is that I want to make something similar above compatible with python 2.5, but when running python2.5 I got: except Exception as msg: ^ SyntaxError: invalid syntax If there's a way (e.g. from __future__ ..., inherited modified Exception class, etc) that could give a solution to keep my code in python 2.6 syntax as above but compatible with python 2.5, that would be appreciated. Many thanks in advance, Alan -- Alan Wilter S. da Silva, D.Sc. - CCPN Research Associate Department of Biochemistry, University of Cambridge. 80 Tennis Court Road, Cambridge CB2 1GA, UK. http://www.bio.cam.ac.uk/~awd28 http://www.bio.cam.ac.uk/%7Eawd28 -- http://mail.python.org/mailman/listinfo/python-list
Re: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
* Standish P, on 16.08.2010 09:20: [garble garble] Nonsense article We look for an exogenous stack cross-posted to [comp.lang.c], [comp.lang.c++], [comp.theory], [comp.lang.python], [comp.lang.forth]. Please refrain from following up on Standish' article. Cheers, - Alf -- blog at url: http://alfps.wordpress.com -- http://mail.python.org/mailman/listinfo/python-list
Re: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
Standish P, 16.08.2010 09:20: We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. What's your use case? Stefan -- http://mail.python.org/mailman/listinfo/python-list
Re: errors and exception
f = open(myfile.txt) for line in f: print line f.close() # This is what the with statement guarantees; so now just do it yourself Not exactly. More like: f = open(myfile.txt) try: for line in f: print line finally: f.close() Daniel -- http://mail.python.org/mailman/listinfo/python-list
Re: errors and exception
On Mon, Aug 16, 2010 at 12:29 AM, Gary Herron gher...@islandtraining.com wrote: On 08/16/2010 12:06 AM, Alan wrote: Hello, I am using things like: snip with open(myfile.txt) as f: for line in f: print line You don't need the new fangled with statement if you want to be compatible with older versions of Python2. (It's nice and convenient, but not necessary.) f = open(myfile.txt) for line in f: print line f.close() # This is what the with statement guarantees; so now just do it yourself Well, technically the equivalent would be: f = open(myfile.txt) try: for line in f: print line finally: f.close() It's just that the for-loop and print happen to be extremely unlikely to throw exceptions; presumably the OP's actual code is more complex. Cheers, Chris -- http://blog.rebertia.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Replace and inserting strings within .txt files with the use of regex
On 10 Αύγ, 01:43, MRAB pyt...@mrabarnett.plus.com wrote:
Íßêïò wrote:
D:\convert.py
File D:\convert.py, line 34
SyntaxError: Non-ASCII character '\xce' in file D:\convert.py on line
34, but no
encoding declared; seehttp://www.python.org/peps/pep-0263.htmlfor
details
D:\
What does it refering too? what character cannot be identified?
Line 34 is:
src_data = src_data.replace( '/body', 'brbrcenterh4font
color=green Áñéèìüò Åðéóêåðôþí: %(counter)d /body' )
Didn't you say that you're using Python 2.7 now? The default file
encoding will be ASCII, but your file isn't ASCII, it contains Greek
letters. Add the encoding line:
# -*- coding: utf-8 -*-
and check that the file is saved as UTF-8.
Also,
for currdir, files, dirs in os.walk('test'):
for f in files:
sctually its for currdir, dirs, filesin os.walk('test'): thats whay
ti couldnt run!! :-)
After changifn this and made some other modification my convertion
script finally run!
Here it is for someone that might want a similar functionality.
==
#!/usr/bin/python
# -*- coding: utf-8 -*-
import re, os, sys
count = 520
for currdir, dirs, files in os.walk('d:\\akis'):
for f in files:
if f.lower().endswith(php):
# get abs path to filename
src_f = os.path.join(currdir, f)
# open php src file
f = open(src_f, 'r')
src_data = f.read()
f.close()
# Grab the id number contained within the php code and
insert it
above all other data
found = re.search( r'PageID = (\d+)', src_data )
if found:
id = found.group(1)
else:
id = count =+ 1
src_data = ( '!-- %s --\n\n' % id ) + src_data
# replace php tags and contents within
src_data = re.sub( r'(?s)\?(.*?)\?', '', src_data )
# add template variables
src_data = src_data.replace( '/body',
'brbrcenterh4font
color=green Αριθμός Επισκεπτών: %(counter)d /body' )
# open same php file for storing modified data
f = open(src_f, 'w')
f.write(src_data)
f.close()
# rename edited .php file to .html extension
dst_f = src_f.replace('.php', '.html')
os.rename( src_f, dst_f )
print ( renaming: %s = %s\n % (src_f, dst_f) )
--
http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
this is heavily x-posted I'm answering from comp.lang.c On 16 Aug, 08:20, Standish P stnd...@gmail.com wrote: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? I'm having trouble understanding your question (I read your whole post before replying). I strongly suspect the only connection your question has with C is that you are using C as your implementation language. I think you're trying to ask a question about memory management. You might be better off asking your question in a general programming new group such as comp.programming (sadly rather quiet these days). Note that C doesn't do automatic garbage collection. Memory is either freed on exit from a scope (stack-like memory lifetime) or explicitly (using free()). Static memory is, conceptually, never freed. Because a stack has push and pop, it is able to release and allocate memory. I'm not sure what you mean by some of the terms you use. In a sense a pop *is* a release. The memory is no longer available for use. We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. exogenous? Why would you do this? Are you envisioning a stack of pointers? The pointers pointing to dynamically allocated memory? Well, yes, sure you could implement this in C. It isn't garbage collection by any standard definition of the term. The algorithm using the stack would have to be perfect to prevent stack overflow or condition of infinite recursion depth. the memory lifetimes must be stack-like (or close to stack-like) This would involve data type checking to filter out invalid input. I'd be more concerned about the memory allocation/dealllocation pattern rather than the data types. The task must be casted in an algorithm that uses the stack. Then the algorithm must be shown to be heuristically or by its metaphor, to be correct using informal reasoning. why informal reasoning? Why not formal reasoning? Are there any standard textbooks or papers that show stacks implemented in C/C++/Python/Forth with malloc/free in push and pop ? well it doesn't sound very hard... If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. don't understand the question. - is forth a general purpose language? Yes - are all algorithms stack based? No some compuations simply need to hang onto memeory for a long time alloc (obj1) alloc (obj2) alloc (obj3) free (obj2) long_computation() free(obj3) free(obj1) this simply isn't stack based. the memory for obj2 cannot be reused on stack based scheme whilst long_computation() is going on. KR ANSI has the example of modular programming showing how to implement a stack but he uses a fixed length array. It is also possibly an endogenous stack. We look for an exogenous stack so that element size can vary. malloc the memory? I see no garbage collection in your post -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Aug 15, 2010, at 11:51 PM, Ian Kelly wrote: On Sun, Aug 15, 2010 at 4:36 PM, Baba raoul...@gmail.com wrote: Hi Mel, indeed i thought of generalising the theorem as follows: If it is possible to buy n, n+1,…, n+(x-1) sets of McNuggets, for some x, then it is possible to buy any number of McNuggets = x, given that McNuggets come in x, y and z packs. so with diophantine_nuggets(7,10,21) i would need 7 passes result:53 but with (10,20,30) and 10 passes i get no result You're on the right track. In the case of (10,20,30) there is no largest exactly purchasable quantity. Any quantity that does not end with a 0 will not be exactly purchasable. I suspect that there exists a largest unpurchasable quantity iff at least two of the pack quantities are relatively prime, but I have made no attempt to prove this. That for sure is not correct; packs of 2, 4 and 7 do have a largest unpurchasable quantity. I'm pretty sure that if there's no common divisor for all three (or more) packages (except one), there is a largest unpurchasable quantity. That is: ∀ i1: ¬(i|a) ∨ ¬(i|b) ∨ ¬(i|c), where ¬(x| y) means x is no divider of y Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 12:47 am, Nick Keighley nick_keighley_nos...@hotmail.com wrote: this is heavily x-posted I'm answering from comp.lang.c On 16 Aug, 08:20, Standish P stnd...@gmail.com wrote: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? I'm having trouble understanding your question (I read your whole post before replying). I strongly suspect the only connection your question has with C is that you are using C as your implementation language. I think you're trying to ask a question about memory management. You might be better off asking your question in a general programming new group such as comp.programming (sadly rather quiet these days). Note that C doesn't do automatic garbage collection. Memory is either freed on exit from a scope (stack-like memory lifetime) or explicitly (using free()). Static memory is, conceptually, never freed. Because a stack has push and pop, it is able to release and allocate memory. I'm not sure what you mean by some of the terms you use. In a sense a pop *is* a release. The memory is no longer available for use. We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. exogenous? Why would you do this? Are you envisioning a stack of pointers? The pointers pointing to dynamically allocated memory? Well, yes, sure you could implement this in C. It isn't garbage collection by any standard definition of the term. I can clarify what I mean. Most books implement a stack with a fixed length array of chars and push chars into it, for eg kr. I have a dynamically allocated array of pointers. The cons cell is allocated as well as the data is allocated for every push and the pointer points to its_curr_val.next. Similarly, every pop would move the pointer to its_curr_val.prev. It would also free the cons cell and the data after making a copy of the data. Below I explain your point on memory hanging. The algorithm using the stack would have to be perfect to prevent stack overflow or condition of infinite recursion depth. the memory lifetimes must be stack-like (or close to stack-like) This would involve data type checking to filter out invalid input. I'd be more concerned about the memory allocation/dealllocation pattern rather than the data types. The task must be casted in an algorithm that uses the stack. Then the algorithm must be shown to be heuristically or by its metaphor, to be correct using informal reasoning. why informal reasoning? Why not formal reasoning? Are there any standard textbooks or papers that show stacks implemented in C/C++/Python/Forth with malloc/free in push and pop ? well it doesn't sound very hard... If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. don't understand the question. - is forth a general purpose language? Yes - are all algorithms stack based? No Does Forth uses stack for all algorithms ? Does it use pointers , ie indirect addressing ? If it can/must use stack then every algorithm could be made stack based. some compuations simply need to hang onto memeory for a long time alloc (obj1) alloc (obj2) alloc (obj3) free (obj2) long_computation() free(obj3) free(obj1) this simply isn't stack based. the memory for obj2 cannot be reused on stack based scheme whilst long_computation() is going on. In theory the memory can be locked by a long_computation() . But a non- stacked based algorithm can also ignore freeing a memory and cause memory leak, just as an improper usage of stack cause the above problem. The purpose of a stack is to hold intermediate results ONLY. Only intermediate results should be below the long_computation, not those that need not wait for it. That is why heuristic or metaphorical thinking which considers all aspects simultaneously in a visual human brain thinking has less chance of error in conceiving such solutions than formal disjoint and symbolic thought. KR ANSI has the example of modular programming showing how to implement a stack but he uses a fixed length array. It is also possibly an endogenous stack. We look for an exogenous stack so that element size can vary. malloc the memory? I see no garbage collection in your post a stack properly used does not need separate garbage collection. freeing is an automatic part of calling pop. Thats the superiority of a stack based algorithm over linked lists of unrestricted kinds. === Standish P stnd...@gmail.com -- http://mail.python.org/mailman/listinfo/python-list
comp.lang.python
www.127760.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Deditor -- pythonic text-editor
I still keep getting more downloads then usual which is awesome, but I still don't get any kind of response! please mail me or reply to this post with what you think, You can tell me that the program sucks but if you want to, do it in such a way that you also describe what exactly is the problem and not just say the total I really need some response because I'm working on version 0.2.1 and I want to know what there should be changed/added -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On 16 Aug, 09:33, Standish P stnd...@gmail.com wrote: On Aug 16, 12:47 am, Nick Keighley nick_keighley_nos...@hotmail.com On 16 Aug, 08:20, Standish P stnd...@gmail.com wrote: this is heavily x-posted I'm answering from comp.lang.c I also note that another poster has suggested you are a troll/loon you seem to be using some computer science-like terms but in an oddly non-standard manner [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? no at all. How can a goldfish whistle? I'm having trouble understanding your question (I read your whole post before replying). I strongly suspect the only connection your question has with C is that you are using C as your implementation language. I think you're trying to ask a question about memory management. You might be better off asking your question in a general programming new group such as comp.programming (sadly rather quiet these days). this still applies Note that C doesn't do automatic garbage collection. Memory is either freed on exit from a scope (stack-like memory lifetime) or explicitly (using free()). Static memory is, conceptually, never freed. Because a stack has push and pop, it is able to release and allocate memory. I'm not sure what you mean by some of the terms you use. In a sense a pop *is* a release. The memory is no longer available for use. We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. exogenous? Why would you do this? Are you envisioning a stack of pointers? The pointers pointing to dynamically allocated memory? Well, yes, sure you could implement this in C. It isn't garbage collection by any standard definition of the term. I can clarify what I mean. Most books implement a stack with a fixed length array of chars and push chars into it, for eg kr. this isn't inherent to a stack implementaion. A stack could be a malloced block of memory or a linked list. I have a dynamically allocated array of pointers. The cons cell is that *what*? Are you trying to implement Lisp in C or something. Try comp.lang.lisp for some help there. Have you read Lisp In Small Pieces? Good fun. allocated as well as the data is allocated for every push and the pointer points to its_curr_val.next. I'm lost. What does a cons cell have to do with a fixed array of pointers? Why do you need dynamic memory? Aren't cons cells usually of fixed size? How can a Lisp-like language use a stack based memory allocation strategy? Similarly, every pop would move the pointer to its_curr_val.prev. It would also free the cons cell and the data after making a copy of the data. Below I explain your point on memory hanging. The algorithm using the stack would have to be perfect to prevent stack overflow or condition of infinite recursion depth. the memory lifetimes must be stack-like (or close to stack-like) This would involve data type checking to filter out invalid input. I'd be more concerned about the memory allocation/dealllocation pattern rather than the data types. The task must be casted in an algorithm that uses the stack. Then the algorithm must be shown to be heuristically or by its metaphor, to be correct using informal reasoning. why informal reasoning? Why not formal reasoning? Are there any standard textbooks or papers that show stacks implemented in C/C++/Python/Forth with malloc/free in push and pop ? well it doesn't sound very hard... If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. don't understand the question. - is forth a general purpose language? Yes - are all algorithms stack based? No Does Forth uses stack for all algorithms ? don't know. Ask the Forth people. Some algoritms are fundamentally not stack based. If you try to implement them in Forth then either some memory isn't claimed as soon as possible (a leak) or there is some way to to have non-stack based memory management. Does it use pointers , ie indirect addressing ? If it can/must use stack then every algorithm could be made stack based. some compuations simply need to hang onto memeory for a long time alloc (obj1) alloc (obj2) alloc (obj3) free (obj2) long_computation() free(obj3) free(obj1) this simply isn't stack based. the memory for obj2 cannot be reused on stack based scheme whilst long_computation() is going on. In theory the memory can be locked by a long_computation(). But a non- stacked based algorithm can also ignore freeing a memory and cause memory leak, just as an improper usage of stack cause the above problem. The purpose of a stack is to hold intermediate results ONLY. no not really Only
When the first line of a file tells something about the other lines
Often the first line of a file tells how to read or interpret the other lines. Depending on the result, you then have to ... - skip the first line, or - treat the first line in another special way, or - treat the first line in the same way as the other lines. I can handle this by opening the file twice, the first time for reading the first line only. I suppose there exists a more elegant solution. Below is the structure of what I do now. Please comment. f = open(file_name,r)# eerste opening file_line = f.readline() special = True if some_condition else False f.close() f = open(file_name,r)# tweede opening if not special: # use first line, read previously stripped_line = file_line.strip() else: # skip first file_line, or treat in another special way: f.next() # read other lines: for file_line in f: stripped_line = file_line.strip() # now do something with stripped_line f.close() egbert -- Egbert Bouwman Keizersgracht 197-II 1016 DS Amsterdam Tel 0(031)20 6257991 -- http://mail.python.org/mailman/listinfo/python-list
GSM to ISO / UCS2 to ISO
HI all, In an effort to avoid re-inventing the wheel so to speak I was wondering if anyone's come across libraries/tools, etc that achieve the same kind of functionality as the tools library in this java app. http://code.google.com/p/ipddump/source/browse/trunk/src/ipddump/tools/Gsm2Iso.java Thanks, cheers James -- -- James Mills -- -- Problems are solved by method -- http://mail.python.org/mailman/listinfo/python-list
Re: When the first line of a file tells something about the other lines
Egbert Bouwman wrote: Often the first line of a file tells how to read or interpret the other lines. Depending on the result, you then have to ... - skip the first line, or - treat the first line in another special way, or - treat the first line in the same way as the other lines. I can handle this by opening the file twice, the first time for reading the first line only. I suppose there exists a more elegant solution. Below is the structure of what I do now. Please comment. f = open(file_name,r)# eerste opening file_line = f.readline() special = True if some_condition else False f.close() f = open(file_name,r)# tweede opening if not special: # use first line, read previously stripped_line = file_line.strip() else: # skip first file_line, or treat in another special way: f.next() # read other lines: for file_line in f: stripped_line = file_line.strip() # now do something with stripped_line f.close() with open(filename) as lines: first_line = next(lines, ) if special(first_line): # ... else: lines = itertools.chain([first_line], lines) for line in lines: # ... -- http://mail.python.org/mailman/listinfo/python-list
Re: Python XML and tables using math
On Aug 16, 4:00 pm, Stefan Behnel stefan...@behnel.de wrote: flebber, 16.08.2010 05:30: I am looking at a project that will import and modify an XML file and then export it to a table. Currently a flat file table system should be fine. I want to export the modified data to the table and then perform a handful of maths(largely simple statistical functions) to the data and then print out the resultant modified tables. I was planning on using Python 2.7 for the project. Has anyone used a guide to acheive something similar? I would like to read up on it so I can assess my options and best methods, any hints or tips? That can usually be done in a couple of lines in Python. The approach I keep recommending is to use cElementTree (in the stdlib), potentially its iterparse() function if the file is too large to easily fit into memory, but the code won't change much either way. You might want to skip through this list a bit, similar questions have been coming up every couple of weeks. The responses often include mostly complete implementations that you can borrow from. Stefan okay I found http://effbot.org/zone/celementtree.htm so I will have a read through there. I have been creating an every expanding macro/VBA project in Excel and due to slightly changin source document - the header order changes - it causes the project to crash out. I was hoping python and XML may be a bit more robust. -- http://mail.python.org/mailman/listinfo/python-list
Re: text to DB
On Aug 14, 11:15 am, Dennis Lee Bieber wlfr...@ix.netcom.com wrote:
On Fri, 13 Aug 2010 09:46:34 -0700 (PDT), Praveen
praveen.python.pl...@gmail.com declaimed the following in
gmane.comp.python.general:
I have a text file in this format
PRA 1:13 2:20 3:5
SRA 1:45 2:75 3:9
TRA 1:2 2:65 3:45
pattern is- Book Chapter:Verses
now i have my DB schema like this
book_id chapter_id versed_id
Off hand, I'd say that's an incomplete schema since there is not
enough information available to reconstruct the input data...
I'd say there should be a second relation containing
book_id book_name
could any one give me suggestion
Is there a possibility that a given book name can appear multiple
times?
--
Wulfraed Dennis Lee Bieber AF6VN
wlfr...@ix.netcom.com HTTP://wlfraed.home.netcom.com/
f = open(/Users/Trellisys/Desktop//BibleDB/Booktable.txt,r)
bk=[]
cv = []
j=1
d={}
for line in f:
for l in line.split():
if l.isalnum():
bk.append(j)
j = j+1
else:
cv.append(l.split(:))
'''for i in l.split(:):
if i.isalpha():
#print i,j
j = j+1
else:
#print i'''
print bk
print cv
output
[1,2,3] but i am not getting how to map chapterId and versesId with
bookId
Regards,
Praveen
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Comparing lists
Hi all, anybody can point me to a description of how the default comparison of list objects (or other iterables) works? Apparently l1 l2 is equivalent to all ( x y for x,y in zip( l1, l2) ), has is shown in the following tests, but I can't find it described anywhere: [1,2,3] [1,3,2] True [1,2,3] [1,2,4] True [1,2,3] [2,2,3] True [1,2,3] [0,1,3] False [1,2,3] [0,2,3] False [1,2,3] [1,1,3] False [1,2,3] [1,2,2] False Ciao --- FB -- http://mail.python.org/mailman/listinfo/python-list
Problem checking an existing browser cookie
# initialize cookie
cookie = Cookie.SimpleCookie()
cookie.load( os.environ.get('HTTP_COOKIE', '') )
mycookie = cookie.get('visitor')
if ( mycookie and mycookie.value != 'nikos' ) or re.search( r'(cyta|
yandex|13448|spider|crawl)', host ) is None:
blabla...
I checked and Chrome has a cookie names visitor with a value of nikos
within.
So, i have to ask why the if fails?
Thank you.
--
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MS Word Document to html conversion
Hi, I am working on application where it requires uploaded document from has to be converted to the html pages.Am searching for the suitable python package i dint found any thing apart from word2html.py.But the word2html.py is not available for download anywhere can any one suggest me how to solve this problem. Thanks in advance Srinivas HN -- http://mail.python.org/mailman/listinfo/python-list
Re: Comparing lists
On Mon, 16 Aug 2010 13:46:07 +0300, Francesco Bochicchio bieff...@gmail.com wrote: anybody can point me to a description of how the default comparison of list objects (or other iterables) works? Sequences of the same type are compared using lexicographical ordering: http://docs.python.org/tutorial/datastructures.html#comparing-sequences-and-other-types -- http://mail.python.org/mailman/listinfo/python-list
Re: Deditor -- pythonic text-editor
On Mon, 16 Aug 2010 01:52:52 -0700, Kruptein wrote: I still keep getting more downloads then usual which is awesome, but I still don't get any kind of response! Welcome to the real world. For every user who sends you an email, you'll probably have 1000 who don't. Or 10,000. please mail me or reply to this post with what you think, You can tell me that the program sucks but if you want to, do it in such a way that you also describe what exactly is the problem and not just say the total You've asked for feedback at least three times now. It's probably time to stop hassling people. When you have another release ready, then you can ask again. Until then, be grateful that people are at least downloading it! I really need some response because I'm working on version 0.2.1 and I want to know what there should be changed/added If nobody asks for any changes, then just keep doing what you're doing. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Python why questions
On Mon, 16 Aug 2010 16:28:46 +1200, Lawrence D'Oliveiro wrote: In message 8crg0effb...@mid.individual.net, Gregory Ewing wrote: For example, the constant term of a polynomial is usually called term 0, not term 1. That is not some kind of ordinal numbering of the terms, that is the power of the variable involved. And polynomials can have negative powers, too. Not so. Polynomials, by definition, are limited to non-negative integer powers. You're thinking of a polynomial quotient, otherwise known as a rational function. http://mathworld.wolfram.com/Polynomial.html -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Pop return from stack?
On Sun, 15 Aug 2010 21:01:04 -0700, Carey Tilden wrote: On Sun, Aug 15, 2010 at 6:43 PM, bvdp b...@mellowood.ca wrote: Not to belabor the point .. but func is not a standard lib module. It's part of a much larger application ... and in that application it makes perfect sense to terminate the application if it encounters an error. I fail to see the problem with this. Why would an APPLICATION raise a error or not exit to the system? For me, the main reason is to ensure the application has only one exit point. There's only one spot to maintain the code for closing files, cleaning up network connections, displaying errors to the user, etc. You mean all the things that Python's garbage collector already does for you? *wink* -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 10:20 am, Standish P stnd...@gmail.com wrote: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? Most programs can be written so that most of their memory allocations are matched by destructors at the same level. However the allocations that can't be written this way typically tend to be the small frequently-called ones used for nodes in dynamic graph objects, or small resizeable buffers to hold strings and the like. This is where you get the performance hit with repeated calls to malloc() and free(). So generally it's not worthwhile writing a stack allocator for a normal program. That's not to say there aren't a few individual cases where it can help performance. (See the chapter Memory games in my book Basic Agorithms for details about memory allocation strategies). -- http://mail.python.org/mailman/listinfo/python-list
Re: Comparing lists
Francesco Bochicchio wrote: Hi all, anybody can point me to a description of how the default comparison of list objects (or other iterables) works? Apparently l1 l2 is equivalent to all ( x y for x,y in zip( l1, l2) ), has is shown in the following tests, but I can't find it described anywhere: [1,2,3] [1,3,2] True [1,2,3] [1,2,4] True [1,2,3] [2,2,3] True [1,2,3] [0,1,3] False [1,2,3] [0,2,3] False [1,2,3] [1,1,3] False [1,2,3] [1,2,2] False Ciao --- FB Quoting http://docs.python.org/reference/expressions.html Tuples and lists are compared lexicographically using comparison of corresponding elements. This means that to compare equal, each element must compare equal and the two sequences must be of the same type and have the same length. If not equal, the sequences are ordered the same as their first differing elements. For example, cmp([1,2,x], [1,2,y]) returns the same as cmp(x,y). If the corresponding element does not exist, the shorter sequence is ordered first (for example, [1,2] [1,2,3]). -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2.7 re.IGNORECASE broken in re.sub?
On Sun, 15 Aug 2010 17:36:07 -0700, Alex Willmer wrote: On Aug 16, 1:07 am, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: You're passing re.IGNORECASE (which happens to equal 2) as a count argument, not as a flag. Try this instead: re.sub(rpython\d\d + '(?i)', Python27, t) 'Python27' Basically right, but in-line flags must be placed at the start of a pattern, or the result is undefined. Pardon me, but that's clearly not correct, as proven by the fact that the above example works. You can say that the flags *should* go at the start, for the sake of efficiency, or ease of comprehension, or tradition, or to appease the Regex Cops who roam the streets beating up those who don't write regexes in the approved fashion. But it isn't true that they *must* go at the front. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Python why questions
On Mon, 16 Aug 2010 12:33:51 +1200, Gregory Ewing wrote:
Ian Kelly wrote:
On Fri, Aug 13, 2010 at 11:53 AM, Martin Gregorie
mar...@address-in-sig.invalid wrote:
real sample[-500:750];
Ugh, no. The ability to change the minimum index is evil.
Not always; it can have its uses, particularly when you're using the
array as a mapping rather than a collection.
Say you have intensity data captured from an X-ray goniometer from 160
degrees to 30 degrees at 0.01 degree resolution. Which is most evil of
the following?
1) real intensity[16000:3000]
for i from lwb intensity to upb intensity
plot(i/100, intensity[i]);
2) double angle[13000];
double intensity[13000];
for (int i = 0; i 13000; i++)
plot(angle[i], intensity[i]);
3) struct
{
double angle;
double intensity
} measurement;
measurement m[13000];
for (int i = 0; i 13000; i++)
plot(m[i].angle, m[i].intensity);
4) double intensity[13000];
for (int i = 0; i 13000; i++)
plot((16000 - i)/100, intensity[i])
To my mind (1) is much clearer to read and far less error-prone to write,
while zero-based indexing forces you to use code like (2), (3) or (4),
all of which obscure rather than clarify what the program is doing.
--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |
--
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Re: Deditor -- pythonic text-editor
Steven D'Aprano wrote: On Mon, 16 Aug 2010 01:52:52 -0700, Kruptein wrote: I still keep getting more downloads then usual which is awesome, but I still don't get any kind of response! Welcome to the real world. For every user who sends you an email, you'll probably have 1000 who don't. Or 10,000. please mail me or reply to this post with what you think, You can tell me that the program sucks but if you want to, do it in such a way that you also describe what exactly is the problem and not just say the total You've asked for feedback at least three times now. It's probably time to stop hassling people. When you have another release ready, then you can ask again. Until then, be grateful that people are at least downloading it! I really need some response because I'm working on version 0.2.1 and I want to know what there should be changed/added If nobody asks for any changes, then just keep doing what you're doing. Or you can introduce a bug; if your users don't start complaining you don't have any... Peter -- http://mail.python.org/mailman/listinfo/python-list
Re: Problem checking an existing browser cookie
Νίκος wrote:
# initialize cookie
cookie = Cookie.SimpleCookie()
cookie.load( os.environ.get('HTTP_COOKIE', '') )
mycookie = cookie.get('visitor')
if ( mycookie and mycookie.value != 'nikos' ) or re.search( r'(cyta|
yandex|13448|spider|crawl)', host ) is None:
blabla...
I checked and Chrome has a cookie names visitor with a value of nikos
within.
So, i have to ask why the if fails?
Maybe it's because != != ==
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Re: Python 2.7 re.IGNORECASE broken in re.sub?
On Aug 15, 8:07 pm, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: On Sun, 15 Aug 2010 16:45:49 -0700, Christopher wrote: I have the following problem: t=Python26 import re re.sub(rpython\d\d, Python27, t) 'Python26' re.sub(rpython\d\d, Python27, t, re.IGNORECASE) 'Python26' re.sub(rPython\d\d, Python27, t, re.IGNORECASE) 'Python27' Is this a known bug? Is it by design for some odd reason? help(re.sub) Help on function sub in module re: sub(pattern, repl, string, count=0) ... You're passing re.IGNORECASE (which happens to equal 2) as a count argument, not as a flag. Try this instead: re.sub(rpython\d\d + '(?i)', Python27, t) 'Python27' Thanks. Somehow I didn't notice that other argument after looking at it a million times. :-) -- http://mail.python.org/mailman/listinfo/python-list
Re: Pop return from stack?
On Sun, 15 Aug 2010 18:43:49 -0700, bvdp wrote: [...] However, I have gotten hit with more than one comment like yours. So, could you please clarify? Is it bad form to exit an application with sys.exit(1) when an error in a file the application is processing is found? My two cents worth... The distinction I like to make is between *planned* and *unplanned* exits. Planned exits are things like the user choosing Quit from the menu, or a command line tool exiting after printing a usage message. Exit the application is part of the application's user interface, and therefore it is appropriate to exit the application. These aren't errors, the exception isn't called SystemError but SystemExit, and it's not necessary to print a traceback. Such exits should usually only exist in the front-end (user-interface) code, rarely or never in the back-end. But *unplanned* exits are errors, and so you should not disguise them as planned exits by raising SystemExit, any more than you would disguise them as a keyboard interruption by raising KeyboardInterrupt. Raise an appropriate exception, and let Python's normal exception-handling code clean up and exit for you. I make one more design choice: if there's an unrecoverable error in user input (as opposed unexpectedly bad data or a program bug), I suppress the traceback, but any other unrecoverable error, I allow it to print. Something vaguely like this: if __name__ == '__main__': try: main() except getopt.GetoptError, e: # Unrecoverable error in command line options. print e.args[0] sys.exit(42) # or whatever value is appropriate except Exception, e: log_exception(e) # whatever... raise SystemExit won't be caught, and will just exit normally. Any other exception won't be caught either, but will lead to a traceback. -- Steven -- http://mail.python.org/mailman/listinfo/python-list
Re: Dump logging configuration
Kxepal wrote: Hi all! Sorry for dumb question if it is - I'd tried to google it before but have found nothing. Is there any way to dump current logging configuration for future loading it via fileConfig/dictConfig? I may be wrong but I don't think so. JM -- http://mail.python.org/mailman/listinfo/python-list
Re: Python why questions
On Mon, Aug 16, 2010 at 9:53 AM, Gregory Ewing greg.ew...@canterbury.ac.nz wrote: On Aug 7, 2010, at 9:14 PM, John Nagle wrote: The languages which have real multidimensional arrays, rather than arrays of arrays, tend to use 1-based subscripts. That reflects standard practice in mathematics. Not always -- mathematicians use whatever starting index is most convenient for the problem at hand. Yes, there are many engineering fields where index starts at 0. Partly for the reason you have stated concerning polynomials, especially since this extend to series, which are pervasive in numerical computing. In linear algebra, though, I remember to have always noted matrices indexes in the [1,n] range, not [0,n-1]. In general, I suspect this is much more a tradition than any kind of very reasoned thinking (and conversely, I find most arguments for 0-indexing and against one-indexing rather ... unconvincing. What's awkward is when you have to constantly change from one to the other). cheers, David -- http://mail.python.org/mailman/listinfo/python-list
Textvariable display in label (GUI design)
hi, pls help me out with the following issue: I wrote a function that uses a for loop that changes a value of a certain variable each iteration. What I want is by clicking a button in GUI (with the command bound to this function) this value each iteration is displayed in a textbox (label). So far only one (starting value) is displayed. thanks, Alex -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 3:20 pm, Standish P stnd...@gmail.com wrote: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? Because a stack has push and pop, it is able to release and allocate memory. We envisage an exogenous stack which has malloc() associated with a push and free() associated with a pop. The algorithm using the stack would have to be perfect to prevent stack overflow or condition of infinite recursion depth. This would involve data type checking to filter out invalid input. The task must be casted in an algorithm that uses the stack. Then the algorithm must be shown to be heuristically or by its metaphor, to be correct using informal reasoning. Are there any standard textbooks or papers that show stacks implemented in C/C++/Python/Forth with malloc/free in push and pop ? If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. KR ANSI has the example of modular programming showing how to implement a stack but he uses a fixed length array. It is also possibly an endogenous stack. We look for an exogenous stack so that element size can vary. === Standish P stnd...@gmail.com Garbage collection doesn't use a stack. It uses a heap, which is in the abstract a collection of memory blocks of different lengths, divided into two lists, generally represented as linked lists: 1. A list of blocks that are free and may be used to store new data 2. A list of blocks that are in use, or haven't been freed (yet) There is no way you could do memory management of all but the most trivial and fixed-length data chunks using a stack. Sure, you could reserve thousands of bytes on the stack for an array but suppose your language allows arrays to grow or shrink. To keep its property of being adjacent, you'd have to do something horrible such as move unrelated data allocated later, which raises all sorts of security issues, doesn't it. A stack, or something which works like a stack (that is, a stack) is a necessary but not sufficient condition for a working C runtime because C functions can call themselves recursively, whether directly or indirectly. If this last condition did not obtain, each function could give the functions it calls some of its own memory and the called function could save a fixed set of non-stacked general registers in that area; this was in fact the practice on IBM 370 and in assembler language at a time when many data processing managers though recursion was a Communist plot. However, data structures of variable size, or data structures that merely take up a lot of space, don't play nice with others on the stack, so, we place their address on the stack and store them in another place, which was named the heap, probably, as a sort of witticism. Gilbert and Sullivan: If anyone anything lacks He'll find it all ready in stacks was wrong, and needs to be brought up to date: You cannot do everything in a stack Unless you code an almighty hack If you're a coding Knight who says, Neep, You'll probably need to implement a heap A pile a heap of benefits you'll reap If only my advice in your brain you'll keep And avoid memory leaks from which data doth seep By using a well-implemented, well structured, and well-documented Heap! [Chorus of Sailors] We will to heart your advice take, and always use a heap! [Soloist] Oh thank you do To this be true And always my sage advice do keep That you always need to use a heap! -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 7:20 pm, Malcolm McLean malcolm.mcle...@btinternet.com wrote: On Aug 16, 10:20 am, Standish P stnd...@gmail.com wrote: [Q] How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ? Most programs can be written so that most of their memory allocations are matched by destructors at the same level. However the allocations that can't be written this way typically tend to be the small frequently-called ones used for nodes in dynamic graph objects, or small resizeable buffers to hold strings and the like. This is where you get the performance hit with repeated calls to malloc() and free(). So generally it's not worthwhile writing a stack allocator for a normal program. That's not to say there aren't a few individual cases where it can help performance. (See the chapter Memory games in my book Basic Agorithms for details about memory allocation strategies). Even if it's a troll, it was droll. In a language that of necessity has a runtime stack or something that works like a stack (eg., a stack) one finds that the need for explicit stacks is lessened. For example, in my compiler for [start shameless plug] Build Your Own .Net Language and Compiler [end shameless plug] I did not need to use an explicit stack to do recursive descent. Instead, I simply called finer grained procedures, passing the compiler state as a parameter, allowing the runtime stack to manage the return. To build an explicit stack in this program would have been folly, for it would have been necessary to either preallocate the stack and thus legislate the maximum complexity of source code, or use a lot of memory management in the pre-existing runtime heap. You didn't tell us you published a book. Can you identify the publisher? -- http://mail.python.org/mailman/listinfo/python-list
Re: Deditor -- pythonic text-editor
On Mon, 16 Aug 2010 14:26:09 +0300, Peter Otten __pete...@web.de wrote: Steven D'Aprano wrote: If nobody asks for any changes, then just keep doing what you're doing. Or you can introduce a bug; if your users don't start complaining you don't have any... Even that doesn't work. They may blog or tweet about it, complain on foreign forums, and set up petitions about it, but they will never, EVER send you an email. It's very disheartening. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2.7 re.IGNORECASE broken in re.sub?
On Aug 16, 12:23 pm, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: On Sun, 15 Aug 2010 17:36:07 -0700, Alex Willmer wrote: On Aug 16, 1:07 am, Steven D'Aprano st...@remove-this- cybersource.com.au wrote: You're passing re.IGNORECASE (which happens to equal 2) as a count argument, not as a flag. Try this instead: re.sub(rpython\d\d + '(?i)', Python27, t) 'Python27' Basically right, but in-line flags must be placed at the start of a pattern, or the result is undefined. Pardon me, but that's clearly not correct, as proven by the fact that the above example works. Undefined includes 'might work sometimes'. I refer you to the Python documentation: Note that the (?x) flag changes how the expression is parsed. It should be used first in the expression string, or after one or more whitespace characters. If there are non-whitespace characters before the flag, the results are undefined. http://docs.python.org/library/re.html#regular-expression-syntax -- http://mail.python.org/mailman/listinfo/python-list
Re: Python why questions
On 2010-08-15, John Nagle na...@animats.com wrote: In retrospect, C's pointer=array concept was a terrible mistake. C arrays are not pointers. -- Neil Cerutti -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2.7 re.IGNORECASE broken in re.sub?
On Aug 16, 1:46 pm, Alex Willmer a...@moreati.org.uk wrote: Note that the (?x) flag changes how the expression is parsed. It should be used first in the expression string, or after one or more whitespace characters. If there are non-whitespace characters before the flag, the results are undefined. http://docs.python.org/library/re.html#regular-expression-syntax Hmm, I found a lot of instances that place (?iLmsux) after non- whitespace characters http://google.com/codesearch?hl=enlr=q=file:\.py[w]%3F$+[^[:space:]%22']%2B\(\%3F[iLmsux]%2B\) including two from the Python unit tests, re_test.py lines 109-110. Perhaps the documentation is overly cautious.. -- http://mail.python.org/mailman/listinfo/python-list
Re: Simple Python Sandbox
On Sat, Aug 14, 2010 at 07:54:11PM -0700, Stephen Hansen wrote:
How are you implementing refusing-names-beginning-with-underscore, out
of curiosity?
I compile the expressions and look into co_names, e.g.:
expr = 0 .__class__
c=compile(expr,,eval)
c.co_names
('__class__',)
regards,
Roland
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About UpdateLayeredWindow
Hello, In the last two weeks I've been trying to properly use UpdateLayeredWindow in Python but I'm only getting errors. I searched a lot on the internet and you are the only person who posted about using ULW in Python. I tried with ctypes and I also tried with win32gui win32api. I got all kinds of errors. In the end I got to error code 5 (ERROR_ACCESS_DENIED) and nothing appears on the screen. Please send me a small working example in Python of UpdateLayeredWindow, either using ctypes or win32gui win32api. My email address is q_cr...@yahoo.com Thank you, Alex -- http://mail.python.org/mailman/listinfo/python-list
passing variables as object attributes
Hello to all I am new to python. I am facing problem to use variables as object attributes. I have to use loop and dynamically add attributes to a object and for this purpose I have to use variables with object names. For example-: Let us say object car has an attribute engine, then varname = engine car.varname = dummy value is giving me Error: object car does not have attribute varname. Please tell me how can I use variables as objects attributes. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
you would need to define a class first with its attiributes and then you may want to initiate the variables by calling the class initilializer On Mon, Aug 16, 2010 at 7:10 PM, Vikas Mahajan vikas.mahaja...@gmail.comwrote: Hello to all I am new to python. I am facing problem to use variables as object attributes. I have to use loop and dynamically add attributes to a object and for this purpose I have to use variables with object names. For example-: Let us say object car has an attribute engine, then varname = engine car.varname = dummy value is giving me Error: object car does not have attribute varname. Please tell me how can I use variables as objects attributes. Thanks. -- http://mail.python.org/mailman/listinfo/python-list -- Nitin Pawar -- http://mail.python.org/mailman/listinfo/python-list
Re: When the first line of a file tells something about the other lines
On Mon, Aug 16, 2010 at 11:59:57AM +0200, Peter Otten wrote: with open(filename) as lines: first_line = next(lines, ) if special(first_line): # ... else: lines = itertools.chain([first_line], lines) for line in lines: # ... Beautiful. And a nice suggestion to read the itertools docs. egbert -- Egbert Bouwman - Keizersgracht 197 II - 1016 DS Amsterdam - 020 6257991 -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
On 16 August 2010 19:23, Nitin Pawar nitinpawar...@gmail.com wrote: you would need to define a class first with its attiributes and then you may want to initiate the variables by calling the class initilializer Actually I have to dynamically add attributes to a object. I am writing python script for FreeCAD software. I am using loop to create multiple cylinders and I am writing following code-: cyname = Cylinder FreeCAD.ActiveDocument.addObject(Part::Cylinder,cyname) FreeCAD.ActiveDocument.cyname.Radius= .5 FreeCAD.ActiveDocument.cyname.Height= 10 And I am getting this error-: AttributeError: 'App.Document' object has no attribute 'cyname' But when I use Cylinder in place of cyname, I am not getting any error. Please help. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
does someone has a binary 32-bit windows installer for arac ?
thanks, Stef Mientki -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
On Aug 16, 10:08 am, Vikas Mahajan vikas.mahaja...@gmail.com wrote: On 16 August 2010 19:23, Nitin Pawar nitinpawar...@gmail.com wrote: you would need to define a class first with its attiributes and then you may want to initiate the variables by calling the class initilializer Actually I have to dynamically add attributes to a object. I am writing python script for FreeCAD software. I am using loop to create multiple cylinders and I am writing following code-: cyname = Cylinder FreeCAD.ActiveDocument.addObject(Part::Cylinder,cyname) FreeCAD.ActiveDocument.cyname.Radius= .5 FreeCAD.ActiveDocument.cyname.Height= 10 And I am getting this error-: AttributeError: 'App.Document' object has no attribute 'cyname' But when I use Cylinder in place of cyname, I am not getting any error. Please help. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
On Aug 16, 10:08 am, Vikas Mahajan vikas.mahaja...@gmail.com wrote: On 16 August 2010 19:23, Nitin Pawar nitinpawar...@gmail.com wrote: you would need to define a class first with its attiributes and then you may want to initiate the variables by calling the class initilializer Actually I have to dynamically add attributes to a object. I am writing python script for FreeCAD software. I am using loop to create multiple cylinders and I am writing following code-: cyname = Cylinder FreeCAD.ActiveDocument.addObject(Part::Cylinder,cyname) FreeCAD.ActiveDocument.cyname.Radius= .5 FreeCAD.ActiveDocument.cyname.Height= 10 And I am getting this error-: AttributeError: 'App.Document' object has no attribute 'cyname' But when I use Cylinder in place of cyname, I am not getting any error. Please help. Thanks. This might work: cyname = Cylinder FreeCAD.ActiveDocument.addObject(Part::Cylinder,cyname) getattr(FreeCAD.ActiveDocument,cyname).Radius= .5 getattr(FreeCAD.ActiveDocument,cyname).Height= 10 -- http://mail.python.org/mailman/listinfo/python-list
how to switch image in tkinter? making it mutable? how?
I have this: image1 = ImageTk.PhotoImage(file = c:\\f1.jpg) image2 = ImageTk.PhotoImage(file = c:\\f2.jpg) imagelist.append(image1) imagelist.append(image2) self.label = tk.Label(image = imagelist[0]) is there a way that i can create a method to switch the display the image2 (imagelist 2nd element) without using label.bind? can i make an image mutable? -- http://mail.python.org/mailman/listinfo/python-list
Re: Dump logging configuration
Jean-Michel Pichavant wrote: Kxepal wrote: Hi all! Sorry for dumb question if it is - I'd tried to google it before but have found nothing. Is there any way to dump current logging configuration for future loading it via fileConfig/dictConfig? I may be wrong but I don't think so. JM Please understand that I don't think such feature exists (to oppose to thinking that I'm not wrong :o) ) JM -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks? No, not really. If you keep the allocated things and free them in reverse order on exit, then well yes, but practically, early free() frees memory for reuse on low memory systems. In this sense not 'reversed' out of order free is essential in some contexts. The question then becomes what is the best heap fragmentation/ compaction strategy and what is the best allocation algorithm to allocate addresses? -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Mon, Aug 16, 2010 at 4:23 AM, Roald de Vries downa...@gmail.com wrote: I suspect that there exists a largest unpurchasable quantity iff at least two of the pack quantities are relatively prime, but I have made no attempt to prove this. That for sure is not correct; packs of 2, 4 and 7 do have a largest unpurchasable quantity. 2 and 7 are relatively prime, so this example fits my hypothesis. I'm pretty sure that if there's no common divisor for all three (or more) packages (except one), there is a largest unpurchasable quantity. That is: ∀ i1: ¬(i|a) ∨ ¬(i|b) ∨ ¬(i|c), where ¬(x|y) means x is no divider of y No. If you take the (2,4,7) example and add another pack size of 14, it does not cause quantities that were previously purchasable to become unpurchasable. Ian -- http://mail.python.org/mailman/listinfo/python-list
question about pdb assignment statements
In this little script: pre import pdb pdb.set_trace() def main(): xm = 123 print(Hello,world!) main() /pre When I run this, I use pdb to step through it until I reach the point in main() where the xm variable has been initialized, and then I try to use pdb to reset the value of xm, and I can't. Does anybody know why? As I understand the documentation, http://docs.python.org/library/pdb.html I *should* be able to do this. [!]statement Execute the (one-line) statement in the context of the current stack frame. Is there something about in the context of the current stack frame that I don't understand? Or is it a bug (or a limitation) in pdb? -- http://mail.python.org/mailman/listinfo/python-list
Re: how to switch image in tkinter? making it mutable? how?
In article 414ff6dd-73ef-48df-bd2b-080a2c710...@h17g2000pri.googlegroups.com, ChrisChia chrischi...@gmail.com wrote: I have this: image1 = ImageTk.PhotoImage(file = c:\\f1.jpg) image2 = ImageTk.PhotoImage(file = c:\\f2.jpg) imagelist.append(image1) imagelist.append(image2) self.label = tk.Label(image = imagelist[0]) is there a way that i can create a method to switch the display the image2 (imagelist 2nd element) without using label.bind? can i make an image mutable? Unfortunately, I don't know the package ImageTk you're using. But at tk level, images are mutable without problem. It seems however that the tcl commands allowing to read an existing image from a file are not exposed at Tkinter level. But it is still possible to send the command to the underlying tcl interpreter to do it: from Tkinter import * root = Tk() image = PhotoImage(file='f1.gif') label = Label(root, image=image) ## When you want to change the image: root.tk.call(image, 'read', 'f2.gif', '-shrink') This will only work with image formats supported in the tcl/tk core, which are basically only GIF so far. BTW, I don't understand why you talk about label.bind If you need to do anything when the label is clicked, you have to make a binding on the label whatever it is. HTH anyway. - Eric - -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 3:14 pm, spinoza spinoza1...@yahoo.com wrote: To build an explicit stack in this program would have been folly, for it would have been necessary to either preallocate the stack and thus legislate the maximum complexity of source code, or use a lot of memory management in the pre-existing runtime heap. The problem is that if you reallocate the stack, you invalidate all pointers to objects on it. So you have to use handles instead. At which point you might as well admit that you are no longer programming in C. You didn't tell us you published a book. Can you identify the publisher?- Hide quoted text - It's a print on demand, by Lulu. O'Reilley said they liked it but they couldn't sell books on C. (I've an open invitation to write a computer book for them in another language). I don't really recommend print on demand. The nice thing is that you can sell the book for about half the price it would cost under a traditional publishing model. The problem is that people still use acceptance by a traditional publisher as a filter. -- http://mail.python.org/mailman/listinfo/python-list
Re: Textvariable display in label (GUI design)
In article 993d9560-564d-47f0-b2db-6f0c6404a...@g6g2000pro.googlegroups.com, Jah_Alarm jah.al...@gmail.com wrote: hi, pls help me out with the following issue: I wrote a function that uses a for loop that changes a value of a certain variable each iteration. What I want is by clicking a button in GUI (with the command bound to this function) this value each iteration is displayed in a textbox (label). So far only one (starting value) is displayed. thanks, Alex First, with posts like this, you're highly unlikely to get any useful answer: please strip down your code to the smallest part that displays the problem, post this code here, explaining what you're expecting and what you're getting. Otherwise, people just won't know what you're talking about unless they have a crystal ball Now using my own crystal ball: if you don't return the control to the GUI each time your variable is increased, the GUI won't get a chance to update itself. Since you seem to use Tkinter (another wild guess), you probably need a call to the update_idletasks method on any Tkinter widget each time you change your TextVariable. HTH - Eric - -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
On Aug 16, 8:40 pm, Vikas Mahajan vikas.mahaja...@gmail.com wrote: Hello to all I am new to python. I am facing problem to use variables as object attributes. I have to use loop and dynamically add attributes to a object and for this purpose I have to use variables with object names. For example-: Let us say object car has an attribute engine, then varname = engine car.varname = dummy value is giving me Error: object car does not have attribute varname. Please tell me how can I use variables as objects attributes. Thanks. I'm not a python expert, so this may not be accurate For me it is easier to define a class that represent the object, and then set attribute for the object. for example : # define a class with no attribute class Car(): pass # instance the class mycar = Car() # dynamically set attribute to the instance newattr = engine setattr(mycar, newattr, dummy value) # or dynamically set attribute to the Class so every instance will inherit it classattr = color setattr(mycar, classattr, yellow) But as I mention, I'm not an expert so maybe it's not a pythonic way to add attribute to an object. Cheers, -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Mon, Aug 16, 2010 at 11:04 AM, Ian Kelly ian.g.ke...@gmail.com wrote: On Mon, Aug 16, 2010 at 4:23 AM, Roald de Vries downa...@gmail.com wrote: I suspect that there exists a largest unpurchasable quantity iff at least two of the pack quantities are relatively prime, but I have made no attempt to prove this. That for sure is not correct; packs of 2, 4 and 7 do have a largest unpurchasable quantity. 2 and 7 are relatively prime, so this example fits my hypothesis. Although now that I think about it some more, there are counter-examples. For example, the pack sizes (6, 10, 15) have a largest unpurchasable quantity of 29, but no two of those are relatively prime. I'm going to revise my hypothesis to state that a largest unpurchasable quantity exists iff some there exists some relatively prime subset of the pack sizes of cardinality 2 or greater. Cheers, Ian -- http://mail.python.org/mailman/listinfo/python-list
Re: Dump logging configuration
On Aug 16, 6:53 pm, Jean-Michel Pichavant jeanmic...@sequans.com wrote: Jean-Michel Pichavant wrote: Kxepal wrote: Hi all! Sorry for dumb question if it is - I'd tried to google it before but have found nothing. Is there any way todumpcurrentloggingconfiguration for future loading it via fileConfig/dictConfig? I may be wrong but I don't think so. JM Please understand that I don't think such feature exists (to oppose to thinking that I'm not wrong :o) ) JM Ah, you have break my dream, but thanks(: It's a pity, because it very handy feature, but now I see a lot of problems to implement it with current logging flexibility. -- http://mail.python.org/mailman/listinfo/python-list
Re: Deditor -- pythonic text-editor
on steven, peter and eliasf: Well okay I'm new to the world of developing programs, if I encounter problems I directly post a bug on the relevant page, that's maybe why I was a bit frustrated :) but what you three say is indeed true.. -- http://mail.python.org/mailman/listinfo/python-list
Re: Pop return from stack?
On Mon, Aug 16, 2010 at 4:18 AM, Steven D'Aprano st...@remove-this-cybersource.com.au wrote: On Sun, 15 Aug 2010 21:01:04 -0700, Carey Tilden wrote: On Sun, Aug 15, 2010 at 6:43 PM, bvdp b...@mellowood.ca wrote: Not to belabor the point .. but func is not a standard lib module. It's part of a much larger application ... and in that application it makes perfect sense to terminate the application if it encounters an error. I fail to see the problem with this. Why would an APPLICATION raise a error or not exit to the system? For me, the main reason is to ensure the application has only one exit point. There's only one spot to maintain the code for closing files, cleaning up network connections, displaying errors to the user, etc. You mean all the things that Python's garbage collector already does for you? Are you actually disagreeing with the point or just poking fun at my examples? If the former, well, phooey. If the latter, c'est la vie. *wink* :-P Carey -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
Vikas Mahajan wrote: On 16 August 2010 19:23, Nitin Pawar nitinpawar...@gmail.com wrote: you would need to define a class first with its attiributes and then you may want to initiate the variables by calling the class initilializer Actually I have to dynamically add attributes to a object. I am writing python script for FreeCAD software. I am using loop to create multiple cylinders and I am writing following code-: cyname = Cylinder FreeCAD.ActiveDocument.addObject(Part::Cylinder,cyname) FreeCAD.ActiveDocument.cyname.Radius= .5 FreeCAD.ActiveDocument.cyname.Height= 10 And I am getting this error-: AttributeError: 'App.Document' object has no attribute 'cyname' But when I use Cylinder in place of cyname, I am not getting any error. Please help. Thanks. obj.attribute = 5 = setattr(obj, attribute, 5) obj.attribute = getattr(obj, attribute) So considering your example, getattr(FreeCAD.ActiveDocument, cyname).Radius = .5 should do the trick. JM -- http://mail.python.org/mailman/listinfo/python-list
Re: Opposite of split
Thanks much, Nope, no homework. This was a serious question from a serious but perhaps simple physicist who grew up with Algol, FORTRAN and Pascal, taught himself VB(A) and is looking for a replacement of VB and finding that in Python. You can guess my age now. Most of my work I do in R nowadays but R is not flexible enough for some file manipulation operations. I use the book by Lutz (Learning Python). The join method for strings is in there. I did not have the book at hand and I was jetlagged too. I do apologize for asking a simple question. I had no idea that some would go to the extent of giving trick solutions for simple, supposedly homework questions. Bear in mind Python is a very feature rich language. You cannot expect all newbies to remember everything. By the way, I had a working program that did what I wanted using still simpler string concatenation. Replaced that now by tab.join([lines[i][k][2] for i in range(5)]), k being a loop counter. Judge for yourself. That is the level I am at after 6 weeks of doing excercises from my programming book on Pascal in Python. Thanks for the help. I do hope there is no entry level for using this group. If there is, I won't meet it for a while. Alex van der Spek D'Arcy J.M. Cain da...@druid.net wrote in message news:mailman.2159.1281917130.1673.python-l...@python.org... On 15 Aug 2010 23:33:10 GMT Steven D'Aprano st...@remove-this-cybersource.com.au wrote: Under what possible circumstances would you prefer this code to the built- in str.join method? I assumed that it was a trap for someone asking for us to do his homework. I also thought that it was a waste of time because I knew that twenty people would jump in with the correct answer because of finally, one that I can answer syndrome. -- D'Arcy J.M. Cain da...@druid.net | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
EOFError with fileinput
Using the fileinput module to process lists of files: for line in fileinput.input(logs): Unfortunately, EOFError does not seem to indicate the end-of-file condition correctly when using fileinput. How would you find the EOF file for all the files in the file list 'logs'? Thank you, Alex van der Spek -- http://mail.python.org/mailman/listinfo/python-list
Re: python strings and {} in Tkinter entry widgets
On Aug 15, 4:41 pm, Chris Hare ch...@labr.net wrote:
I have some code that pulls a value from a database. In this case, it is
three space delimited words. When I display the value in a Tkinter.Entry
widget, the text has curly braces around it, even when there are none in the
surrounding the text in the database.
Is this normal, and how do I prevent it or remove them correctly before
displaying the text in the Entry widget?
Python ['', '', ''] == Tcl {{} {} {}}
Python 'a word' == Tcl {a word}
You are getting a literal translation occurring, and you need to split/
join or index the items properly. Without being more clear how you
want to represent your data, what you need isn't clear. Perhaps you
just need to reference the first index of the variable, or ... who
knows, there are lots of possibilities.
Jeff
--
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Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Aug 16, 2010, at 5:04 PM, Ian Kelly wrote: On Mon, Aug 16, 2010 at 4:23 AM, Roald de Vries downa...@gmail.com wrote: I suspect that there exists a largest unpurchasable quantity iff at least two of the pack quantities are relatively prime, but I have made no attempt to prove this. That for sure is not correct; packs of 2, 4 and 7 do have a largest unpurchasable quantity. 2 and 7 are relatively prime, so this example fits my hypothesis. I now notice I misread your post (as 'iff the least two pack quantities are relatively prime') I'm pretty sure that if there's no common divisor for all three (or more) packages (except one), there is a largest unpurchasable quantity. That is: ∀ i1: ¬(i|a) ∨ ¬(i|b) ∨ ¬(i|c), where ¬(x|y) means x is no divider of y No. If you take the (2,4,7) example and add another pack size of 14, it does not cause quantities that were previously purchasable to become unpurchasable. Then what is the common divisor of 2, 4, 7 and 14? Not 2 because ¬(2| 7), not anything higher than 2 because that's no divisor of 2. Cheers, Roald -- http://mail.python.org/mailman/listinfo/python-list
Re: Opposite of split
Perhaps the ones here who think I was trying to make you do my homework can
actually help me for real. Since I run my own company (not working for any
of the big ones) I can't afford official training in anything. So I teach
myself, help is always welcome and sought for. If that feels like doing
homework for me, so be it.
The fact is that I do try to learn Python. It can do things I thought
required much more coding. Look at the attached. It builds a concordance
table first. That was an excercise from a book on Pascal programming. In
Pascal the solution is 2 pages of code. In Python it is 8 lines. Beautiful!
Anybody catches any other ways to improve my program (attached), you are
most welcome. Help me learn, that is one of the objectives of this
newsgroup, right? Or is it all about exchanging the next to impossible
solution to the never to happen unreal world problems?
Regards,
Alex van der Spek
D'Arcy J.M. Cain da...@druid.net wrote in message
news:mailman.2159.1281917130.1673.python-l...@python.org...
On 15 Aug 2010 23:33:10 GMT
Steven D'Aprano st...@remove-this-cybersource.com.au wrote:
Under what possible circumstances would you prefer this code to the
built-
in str.join method?
I assumed that it was a trap for someone asking for us to do his
homework. I also thought that it was a waste of time because I knew
that twenty people would jump in with the correct answer because of
finally, one that I can answer syndrome.
--
D'Arcy J.M. Cain da...@druid.net | Democracy is three wolves
http://www.druid.net/darcy/| and a sheep voting on
+1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner.
#! usr/bin/env python
# Merge log files to autolog file
import os
import fileinput
#top='C:\\Documents and Settings\\avanderspek\\My
Documents\\CiDRAdata\\Syncrude\\CSL\\August2010'
top='C:\\Users\\ZDoor\\Documents\\CiDRA\\Syncrude\CSL\\August2010'
i,j,k=0,0,0
date={}
fps=0.3048
tab='\t'
bt='-999.25'+'\t''-999.25'+'\t''-999.25'+'\t''-999.25'+'\t'+'-999.25'
al='Status'+'\t'+'State'+'\t'+'-999.25'
for root,dirs,files in os.walk(top):
#Build a concordance table of days on which data was collected
for name in files:
ext=name.split('.',1)[1]
if ext=='txt':
dat=name.split('_')[1].split('y')[1]
if dat in date.keys():
date[dat]+=1
else:
date[dat]=1
print 'Concordance table of days:'
print date
print 'List of files processed:'
#Build a list of same day filenames, 5 max for a profile meter,skip first
and last days
for f in sorted(date.keys())[2:-1]:
logs=[]
for name in files:
ext=name.split('.')[1]
if ext=='txt':
dat=name.split('_')[1].split('y')[1]
if dat==f:
logs.append(os.path.join(root,name))
#Open the files and read line by line
datsec=False
lines=[[] for i in range(5)]
fn=0
for line in fileinput.input(logs):
if line.split()[0]=='DataID':
datsec=True
ln=0
if datsec:
lines[fn].append(line.split())
ln+=1
if ln==10255:
datsec=False
fileinput.nextfile()
fn+=1
print fileinput.filename().rsplit('\\',1)[1]
fileinput.close()
aut='000_AutoLog'+f+'.log'
out=os.path.join(root,aut)
alf=open(out,'w')
alf.write('Timestamp (mm/dd/ hh:mm:ss) VF 1VF 2VF 3
VF 4VF 5Q 1 Q 2 Q 3 Q 4 Q 5 Status State Metric
Band Temperature 1 Band Temperature 2 Band Temperature 3 Band
Temperature 4 Band Temperature 5 SPL 1 SPL 2 SPL 3 SPL 4 SPL
5'+'\n')
for wn in range(1,10255,1):
for i in range(5):
lines[i][wn][2]=str(float(lines[i][wn][2])/fps)
tp=lines[0][wn][0]+' '+lines[0][wn][1]
vf=tab.join([lines[i][wn][2] for i in range(5)])
vq=tab.join([lines[i][wn][3] for i in range(5)])
vs=tab.join([lines[i][wn][4] for i in range(5)])
#sf=tab.join([lines[i][wn][5] for i in range(5)])
#sq=tab.join([lines[i][wn][6] for i in range(5)])
#ss=tab.join([lines[i][wn][7] for i in range(5)])
alf.write(tp+'\t'+vf+'\t'+vq+'\t'+al+'\t'+bt+'\t'+vs+'\n')
alf.close()
print Done
--
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Newbie: strftime object error message
I am trying to call a function with a couple additional parameters. Unfortunately, for whatever reason I am unable to get this to work. I am assuming that line is not passing correctly but I don't understand why??? I can't share all of the code because it has IP in it but below are the pertinent snippets. Thanks in advance! ## PY: 3.1.2 FUNCTION CALL: text_file = open(file_name, r) for line in text_file: new_foo = pop_time(current_time, line) # current_time = datetime.datetime.now() FUNCTION: def pop_time(line, cur_time): global new_string global current_time # Generate random time between 0 and 30 seconds # Changes the time delta every time function is run rand_time = random.randint(0, 30) delta_time = datetime.timedelta(seconds=rand_time) # Sets the time format for string output format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) ERROR MSG: format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) AttributeError: 'str' object has no attribute 'strftime' NOTE: current_time prints within the function, line does not -- http://mail.python.org/mailman/listinfo/python-list
Re: EOFError with fileinput
On 16/08/2010 17:29, Alex van der Spek wrote: Using the fileinput module to process lists of files: for line in fileinput.input(logs): Unfortunately, EOFError does not seem to indicate the end-of-file condition correctly when using fileinput. How would you find the EOF file for all the files in the file list 'logs'? Thank you, Alex van der Spek I'm not sure exactly what you're asking here. Could you a brief description as to what you're trying to achieve, then put the question again. Cheers. Mark Lawrence. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to switch image in tkinter? making it mutable? how?
On Aug 16, 7:30 am, ChrisChia chrischi...@gmail.com wrote: I have this: image1 = ImageTk.PhotoImage(file = c:\\f1.jpg) image2 = ImageTk.PhotoImage(file = c:\\f2.jpg) imagelist.append(image1) imagelist.append(image2) self.label = tk.Label(image = imagelist[0]) is there a way that i can create a method to switch the display the image2 (imagelist 2nd element) without using label.bind? can i make an image mutable? self.label.configure(image = imagelist[1]) will change the image displayed. With PIL images, you can use image1.fromstring(...) that should have a similar effect, in that it changes the underlying image data and the label will display that. Whether you need to label.bind or something else to effect this change is up to you. You could have it happen on a timer, triggered by an event, or randomly effected by solar flares, depending on your application's needs. Jeff -- http://mail.python.org/mailman/listinfo/python-list
Re: Opposite of split
On Mon, 16 Aug 2010 18:26:46 +0200 Alex van der Spek zd...@xs4all.nl wrote: Nope, no homework. This was a serious question from a serious but perhaps simple physicist who grew up with Algol, FORTRAN and Pascal, taught himself VB(A) and is looking for a replacement of VB and finding that in Python. You can guess my age now. Most of my work I do in R nowadays but R is not flexible enough for some file manipulation operations. I use the book by Lutz (Learning Python). The join method for strings is in there. I did not have the book at hand and I was jetlagged too. I do apologize for asking a simple question. I'm not actually the one that presented the convuluted example. I think the one who did just felt that someone had a question and they were passing it to the group instead of doing a simple Google search. The solution he posted looked like something designed to make the teacher scratch his head and ask embarrassing questions of the student. Thanks for the help. I do hope there is no entry level for using this group. If there is, I won't meet it for a while. I think that the only thing people expect is that you do a quick search first and show that you have tried first. Some questions have been asked and answered so many times that a search of the archives finds what you want without waiting for an answer. -- D'Arcy J.M. Cain da...@druid.net | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
@All Thanks a lot. getattr and setattr functions solved my problem. -- http://mail.python.org/mailman/listinfo/python-list
How to convert bytearray into integer?
Hi there, Recently I'm facing a problem to convert 4 bytes on an bytearray into an 32-bit integer. So far as I can see, there're 3 ways: a) using struct module, b) using ctypes module, and c) manually manipulation. Are there any other ways? My sample is as following: - import struct import ctypes def test_struct(buf, offset): return struct.unpack_from(I, buf, offset)[0] def test_ctypes(buf, offset): return ctypes.c_uint32.from_buffer(buf, offset).value def test_multi(buf, offset): return buf[offset] + (buf[offset+1] 8) + (buf[offset+2] 16) + (buf[offset+3] 24) buf_w = bytearray(5) buf_w[1] = 1 buf_r = buffer(buf_w) if __name__ == '__main__': import timeit t1 = timeit.Timer(test_struct(buf_r, 1), from __main__ import test_struct, buf_r) t2 = timeit.Timer(test_ctypes(buf_w, 1), from __main__ import test_ctypes, buf_w) t3 = timeit.Timer(test_multi(buf_w, 1), from __main__ import test_multi, buf_w) print t1.timeit(number=1000) print t2.timeit(number=1000) print t3.timeit(number=1000) - Yet the results are bit confusing: - number = 1 0.0081958770752 0.012549161911 0.0112121105194 number = 1000 0.00087308883667 0.00125789642334 0.00110197067261 number = 100 0.917911529541 # 9.17911529541e-05 0.000133991241455 0.00011420249939 number = 10 1.69277191162e-05 2.19345092773e-05 1.69277191162e-05 number = 1 1.00135803223e-05 1.00135803223e-05 5.96046447754e-06 - As the number of benchmarking loops decreasing, method c which is manually manipulating overwhelms the former 2 methods. However, if number == 10K, the struct method wins. Why does it happen? Thanks, Jacky (jacky.chao.wang#gmail.com) -- http://mail.python.org/mailman/listinfo/python-list
Re: python strings and {} in Tkinter entry widgets
On Aug 16, 2010, at 11:40 AM, Jeff Hobbs wrote:
On Aug 15, 4:41 pm, Chris Hare ch...@labr.net wrote:
I have some code that pulls a value from a database. In this case, it is
three space delimited words. When I display the value in a Tkinter.Entry
widget, the text has curly braces around it, even when there are none in the
surrounding the text in the database.
Is this normal, and how do I prevent it or remove them correctly before
displaying the text in the Entry widget?
Python ['', '', ''] == Tcl {{} {} {}}
Python 'a word' == Tcl {a word}
You are getting a literal translation occurring, and you need to split/
join or index the items properly. Without being more clear how you
want to represent your data, what you need isn't clear. Perhaps you
just need to reference the first index of the variable, or ... who
knows, there are lots of possibilities.
Jeff
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Actually I want all of the words, as they form the name of an organization
entered by the user. So the space delimited words should be displayed without
the {} in the tkinker entry box. The contents of the widget is a persons first
and last name, space delimited
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Re: Opposite of split
On Mon, 16 Aug 2010 18:44:08 +0200 Alex van der Spek zd...@xs4all.nl wrote: Perhaps the ones here who think I was trying to make you do my homework can You keep replying to my message but as I pointed out in my previous message, I'm not the one who thought that you posted a homework question. I'm the one who thought that the other poster thought that you posted a homework question. Honestly, while I thought it was a question that could have been answered faster with a Google search, it did not look like a homework question to me. actually help me for real. Since I run my own company (not working for any of the big ones) I can't afford official training in anything. So I teach myself, help is always welcome and sought for. If that feels like doing homework for me, so be it. Well, it is home work but there is nothing wrong with asking for help anyway. When people complain about homework questions it is generally because someone has posted the question verbatim from the assignment and asks for a complete solution. That's annoying. What you have done here is good because you show some work and ask for help with it. Slightly better would be to ask specific questions about areas that you are struggling with but this is good. The fact is that I do try to learn Python. It can do things I thought required much more coding. Look at the attached. It builds a concordance table first. That was an excercise from a book on Pascal programming. In Pascal the solution is 2 pages of code. In Python it is 8 lines. Beautiful! I guess the real entry level test here is that you have to be smart enough to choose Python since it is the best language. You pass. :-) -- D'Arcy J.M. Cain da...@druid.net | Democracy is three wolves http://www.druid.net/darcy/| and a sheep voting on +1 416 425 1212 (DoD#0082)(eNTP) | what's for dinner. -- http://mail.python.org/mailman/listinfo/python-list
How can I bundle a PyGTK program in windows so my users don't need to install Python or the GTK+ libs?
I found this question on http://faq.pygtk.org/index.py?file=faq21.005.htpreq=show but the answer did not help me. For example I have a simple program below that I would like to 'compile' with py2exe (or anything else if it's simpler) to run in windows as a single bundled executable file with no installation (no INNO setup), and no requirements for gtk or python installations. I doesn't matter if the .exe file is 30 MB to only display a hello world app, as long as it works. (although the smaller the better) The application already works in my windows test environment because I have installed python 2.6 with pygtk and a gtk bundle. Can someone please provide some simple and clear instructions on how I can do this? Thanks, Waspinator simple.py --- import gtk window = gtk.Window() window.set_title(PyGTK Test Window) window.connect(destroy, gtk.main_quit) window.show_all() gtk.main() --- -- http://mail.python.org/mailman/listinfo/python-list
Re: EXOR or symmetric difference for the Counter class
On 14 Aug, 18:14, Raymond Hettinger pyt...@rcn.com wrote:
On Aug 12, 1:20 pm, Paddy paddy3...@googlemail.com wrote:
I find myself needing to calculate the difference between two Counters
or multisets or bags.
I want those items that are unique to each bag.
Tell us about your use cases. I'm curious how a program would ascribe
semantic meaning to the result. The phrase unique to each bag
doesn't quite cover it, perhaps something like number in either
source above the minimum held in common.
AFAICT, I've never needed something like this as a primitive. Even
the xor operation for regular sets is rarely used.
I know how to
calculate it:
b = Counter(a=1, b=2)
c = Counter(a=3, b=1)
diff = (b - c) + (c - b)
diff
Counter({'a': 2, 'b': 1})
That seems simple enough.
You could also use:
diff = (b | c) - (b c) # max(b,c) - min(b,c)
Raymond
Hi Raymond and others,
Lets say you have two *sets* of integers representing two near-copies
of some system, then a measure of their difference could be calculated
as:
len(X.symmetric_difference(Y)) / (len(X) + len(Y)) * 100 %
If the two collections of integers are allowed duplicates then you
need a Counter/bag/multi-set type and the diff calculation I gave
originally.
Thanks.
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Re: Newbie: strftime object error message
On 16/08/2010 17:47, fuglyducky wrote: I am trying to call a function with a couple additional parameters. Unfortunately, for whatever reason I am unable to get this to work. I am assuming that line is not passing correctly but I don't understand why??? I can't share all of the code because it has IP in it but below are the pertinent snippets. Thanks in advance! ## PY: 3.1.2 FUNCTION CALL: text_file = open(file_name, r) for line in text_file: new_foo = pop_time(current_time, line) # current_time = datetime.datetime.now() FUNCTION: def pop_time(line, cur_time): Look at the two arguments to pop_time, when you make the actual call they are swapped. global new_string global current_time # Generate random time between 0 and 30 seconds # Changes the time delta every time function is run rand_time = random.randint(0, 30) delta_time = datetime.timedelta(seconds=rand_time) # Sets the time format for string output format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) ERROR MSG: format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) AttributeError: 'str' object has no attribute 'strftime' NOTE: current_time prints within the function, line does not HTH. Mark Lawrence. -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: strftime object error message
fuglyducky wrote: I am trying to call a function with a couple additional parameters. Unfortunately, for whatever reason I am unable to get this to work. I am assuming that line is not passing correctly but I don't understand why??? [snip] The function's parameters are the wrong way round. -- http://mail.python.org/mailman/listinfo/python-list
Re: EOFError with fileinput
Here is an excerpt. It works because the end condition is a fixed number
(ln==10255), the approximate number of data lines in a file. If I replace
that condition by EOFError, the program does not do the intended work. It
appears as if EOFError is always true in this case.
+++
for line in fileinput.input(logs):
if line.split()[0]=='DataID':
datsec=True
ln=0
if datsec:
lines[fn].append(line.split())
ln+=1
if ln==10255:
datsec=False
fileinput.nextfile()
fn+=1
print fileinput.filename().rsplit('\\',1)[1]
fileinput.close()
+++
Regards,
Alex van der Spek
Alex van der Spek zd...@xs4all.nl wrote in message
news:4c696751$0$22940$e4fe5...@news.xs4all.nl...
Using the fileinput module to process lists of files:
for line in fileinput.input(logs):
Unfortunately, EOFError does not seem to indicate the end-of-file
condition correctly when using fileinput.
How would you find the EOF file for all the files in the file list 'logs'?
Thank you,
Alex van der Spek
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Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Aug 16, 1:23 am, Roald de Vries downa...@gmail.com wrote: On Aug 15, 2010, at 11:51 PM, Ian Kelly wrote: On Sun, Aug 15, 2010 at 4:36 PM, Baba raoul...@gmail.com wrote: Hi Mel, indeed i thought of generalising the theorem as follows: If it is possible to buy n, n+1,…, n+(x-1) sets of McNuggets, for some x, then it is possible to buy any number of McNuggets = x, given that McNuggets come in x, y and z packs. so with diophantine_nuggets(7,10,21) i would need 7 passes result:53 but with (10,20,30) and 10 passes i get no result You're on the right track. In the case of (10,20,30) there is no largest exactly purchasable quantity. Any quantity that does not end with a 0 will not be exactly purchasable. I suspect that there exists a largest unpurchasable quantity iff at least two of the pack quantities are relatively prime, but I have made no attempt to prove this. That for sure is not correct; packs of 2, 4 and 7 do have a largest unpurchasable quantity. But 2 is coprime to 7. I think a better counterexample is 6, 10, 15; no two are coprime, but there is a largest unpurchasable quantity. I'm pretty sure that if there's no common divisor for all three (or more) packages (except one), there is a largest unpurchasable quantity. That is: ∀ i1: ¬(i|a) ∨ ¬(i|b) ∨ ¬(i|c), where ¬(x| y) means x is no divider of y It's easy to prove that there is a largest unpurchasble quantity iff gcd(x,y,z) = 1. First, suppose d = gcd(x, y, z); then for some x', y', z' we have that x = d*x', y = d*y', z = d*z'; and so for any a, b, c: a*x + b*y + c*z = a*d*x' + b*d*y' + c*d*z' = d*(a*x' + b*y' + c*z') which means that d must always divide the total number of nuggets purchasable; thus if d 1, there is no largest unpurchasable quantity (you cannot purchase n*d + 1 nuggets for any n). To go the other way, if d = 1, then there exists integers (not neccessarily positive) such that a*x + b*y + c*z = 1 so therefore (a*x)*x + (b*x)*y + (c*x)*z = x Choose A, B, and C to be positive integers with A + a*x = 0 B + b*x = 0 C + c*x = 0 Then we get a sequence of x consecutive numbers, all purchasable, via (A + i*a)*x + (B + i*b)*x + (C + i*c)*z = (Ax + By + Cz) + i*(ax + by cz) = (Ax + By + Cz) + i with i in range(x). The next consecutive number is then achieved via (Ax + By + Cz) + x = (A+1)x + By + Cz and so on. Cheers - Chas -- http://mail.python.org/mailman/listinfo/python-list
os.stat st_mtime problem
Hello,
Im stuck with this problem:
I would like to os.stat st_mtime to copy only the files that have different
modification date.
so I found something on internet using this kind of line:
if os.stat(dest).st_mtime - os.stat(src).st_mtime 1:
shutil.copy2 (src, dst)
So I adapted it to my script like that:
if sys.argv[1] == 'update':
if os.stat(localPath).st_mtime != os.stat(networkPath).st_mtime:
os.system('xcopy /E /I /Q /Y %s %s' % (networkPath,
localPath))
else:
print Everything match
localPath is equal to : c:\test\prod\
and networkPath to : d:\test\prod\
the content of this paths is another directory: v001, where there some tga
files.
Now I dont even know if os.stat compare the modified version of every files
contained in localPath and networkPath, or does it compare only the v001
info ?
If there a way to do it for every file ?
Thank you !
(PS: I want to avoid filecmp :p)
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Re: How to convert bytearray into integer?
On Monday 16 August 2010, it occurred to Jacky to exclaim: Hi there, Recently I'm facing a problem to convert 4 bytes on an bytearray into an 32-bit integer. So far as I can see, there're 3 ways: a) using struct module, Yes, that's what it's for, and that's what you should be using. b) using ctypes module, and Yeeaah, that would work, but that's really not what it's for. from_buffer wants a writable buffer interface, which is unlikely to be what you want. c) manually manipulation. Well, yes, you can do that, but it gets messy when you're working with more complex data structures, or you have to consider byte order. Are there any other ways? You could write a C extension module tailored to your specific purpose ;-) number = 1 1.00135803223e-05 1.00135803223e-05 5.96046447754e-06 - As the number of benchmarking loops decreasing, method c which is manually manipulating overwhelms the former 2 methods. However, if number == 10K, the struct method wins. Why does it happen? struct wins because it's built for the job. As for the small numbers: don't take these numbers seriously. Just don't. This may be caused by the way your OS's scheduler handles things for all I know. If there is an explanation for this unscientific observation, I have two guesses what it might be: * struct and ctypes still need to do some setup work, or something * somebody is optimising something, but doesn't know what they should be optimising in the first place after only a few iterations. -- http://mail.python.org/mailman/listinfo/python-list
Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
On Mon, Aug 16, 2010 at 12:43 PM, Roald de Vries downa...@gmail.com wrote: I'm pretty sure that if there's no common divisor for all three (or more) packages (except one), there is a largest unpurchasable quantity. That is: ∀ i1: ¬(i|a) ∨ ¬(i|b) ∨ ¬(i|c), where ¬(x|y) means x is no divider of y No. If you take the (2,4,7) example and add another pack size of 14, it does not cause quantities that were previously purchasable to become unpurchasable. Then what is the common divisor of 2, 4, 7 and 14? Not 2 because ¬(2|7), not anything higher than 2 because that's no divisor of 2. Ah, I misread what you meant as well. -- http://mail.python.org/mailman/listinfo/python-list
Re: passing variables as object attributes
On 8/16/2010 9:40 AM, Vikas Mahajan wrote:
Hello to all
I am new to python.
Hi, welcome to Python.
Hint 1: 'Variable' is a rather loose term with many meanings. Better to
think in terms of 'name' ('identifier'), which is specifically defined,
and 'object'.
I am facing problem to use variables as object attributes.
Your problem is that you have a attribute name stored in a string
object, rather than being an unquoted literal in the code.
I have to use loop and dynamically add attributes to a
object and for this purpose I have to use variables with object names.
You have to use strings with attribute names. Not uncommon
For example-:
Let us say object car has an attribute engine, then
varname = engine
car.varname = dummy value
setattr(car, varname, dummy value)
is the runtime replacement for
car.engine = dummy value
Note that 'setattr(car, engine, dummy value)' would work but is
never needed, since if you have the attribute name itself, you just
write the assignment.
hasattr and getattr are similar.
--
Terry Jan Reedy
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Re: looping through possible combinations of McNuggets packs of 6, 9 and 20
Hi Chas, Roald, These are all complicated formula that i believe are not expected at this level. If you look at the source (see my first submission) you will see that this exercise is only the second in a series called Introduction to Programming. Therefore i am convinced that there is a much simpler solution. Now, i believe that the number of consecutive passes required to make this work is equal to the smallest number of pack sizes. So if we have packs of (9,12,21) the number of passes needed would be 9 and the theorem would read If it is possible to buy n,n+1,n+2,...n+8 nuggets it is possible to buy any number of nuggets = 9 given that they come in packs of 9,12,21 However i turn in circles because i don't seem to get any results for some random pack combinations like (9,12,21) or (10,20,30). The must always be a solution i'm thinking, be it the smallest pack - 1 Thoughts? tnx Raoul -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On 8/15/10 10:33 PM, Standish P wrote: ... I don't understand a lot of your post (and it's clear that I'm not alone). I don't know whether it's a (human) language problem or simply an issue of your having read too many books and not having enough practical experience, but at least I can try to address the Forth questions. If Forth is a general processing language based on stack, is it possible to convert any and all algorithms to stack based ones and thus avoid memory leaks since a pop automatically releases memory when free is an intrinsic part of it. Forth uses two stacks. The data stack is used for passing parameters between subroutines (words) and is completely under the control of the programmer. Words expect parameters on this stack; they remove them, and leave only explicit results. The return stack is used primarily for return addresses when words are called, although it is also available for auxiliary uses under guidelines which respect the primary use for return addresses. Although implementations vary, in most Forths stacks grow from a fixed point (one for each stack) into otherwise-unused memory. The space involved is allocated when the program is launched, and is not managed as a heap and allocated or deallocated by any complicated mechanism. On multitasking Forth systems, each task has its own stacks. Where floating point is implemented (Forth's native arithmetic is integer-based), there is usually a separate stack for floats, to take advantage of hardware FP stacks. - is forth a general purpose language? Yes - are all algorithms stack based? No Does Forth uses stack for all algorithms ? Does it use pointers , ie indirect addressing ? If it can/must use stack then every algorithm could be made stack based. Forth uses its data stack for parameter passing and storage of temporary values. It is also possible to define variables, strings, and arrays in memory, in which case their addresses may be passed on the data stack. Forth is architecturally very simple. Memory allocations for variables, etc., are normally static, although some implementations include facilities for heaps as needed by applications. Hope this helps. If you are interested in learning more about Forth, there are several books available (try Amazon). Get one of the more recent ones, some of which I wrote. Cheers, Elizabeth -- == Elizabeth D. Rather (US Canada) 800-55-FORTH FORTH Inc. +1 310.999.6784 5959 West Century Blvd. Suite 700 Los Angeles, CA 90045 http://www.forth.com Forth-based products and Services for real-time applications since 1973. == -- http://mail.python.org/mailman/listinfo/python-list
Re: How far can stack [LIFO] solve do automatic garbage collection and prevent memory leak ?
On Aug 16, 12:38 am, Alf P. Steinbach /Usenet alf.p.steinbach +use...@gmail.com wrote: * Standish P, on 16.08.2010 09:20: [garble garble] Nonsense article We look for an exogenous stack cross-posted to [comp.lang.c], [comp.lang.c++], [comp.theory], [comp.lang.python], [comp.lang.forth]. Please refrain from following up on Standish' article. I am sorry that I did not post one of those porn baiting spams featuring YOUR MOTHER NUDE that you so like for others to see - AND - that you never complain about. Go and continue with your work and dont mess in my threads. Cheers, Standish Cheers, - Alf -- blog at url:http://alfps.wordpress.com -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie: strftime object error message
On Aug 16, 10:27 am, Mark Lawrence breamore...@yahoo.co.uk wrote: On 16/08/2010 17:47, fuglyducky wrote: I am trying to call a function with a couple additional parameters. Unfortunately, for whatever reason I am unable to get this to work. I am assuming that line is not passing correctly but I don't understand why??? I can't share all of the code because it has IP in it but below are the pertinent snippets. Thanks in advance! ## PY: 3.1.2 FUNCTION CALL: text_file = open(file_name, r) for line in text_file: new_foo = pop_time(current_time, line) # current_time = datetime.datetime.now() FUNCTION: def pop_time(line, cur_time): Look at the two arguments to pop_time, when you make the actual call they are swapped. global new_string global current_time # Generate random time between 0 and 30 seconds # Changes the time delta every time function is run rand_time = random.randint(0, 30) delta_time = datetime.timedelta(seconds=rand_time) # Sets the time format for string output format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) ERROR MSG: format_time = cur_time.strftime(%Y-%m-%d %H:%M:%S) AttributeError: 'str' object has no attribute 'strftime' NOTE: current_time prints within the function, line does not HTH. Mark Lawrence. Oh jeez!!! Thanks! Man...looking at this stuff for so long it's easy to miss the obvious!!! Thanks and sorry for the waste of time. -- http://mail.python.org/mailman/listinfo/python-list
Re: os.stat st_mtime problem
Alban Nona wrote:
Hello,
Im stuck with this problem:
I would like to os.stat st_mtime to copy only the files that have
different modification date.
so I found something on internet using this kind of line:
if os.stat(dest).st_mtime - os.stat(src).st_mtime 1:
shutil.copy2 (src, dst)
So I adapted it to my script like that:
if sys.argv[1] == 'update':
if os.stat(localPath).st_mtime != os.stat(networkPath).st_mtime:
os.system('xcopy /E /I /Q /Y %s %s' % (networkPath,
localPath))
else:
print Everything match
localPath is equal to : c:\test\prod\
and networkPath to : d:\test\prod\
the content of this paths is another directory: v001, where there some
tga files.
Now I dont even know if os.stat compare the modified version of every
files contained in localPath and networkPath, or does it compare only
the v001 info ?
If there a way to do it for every file ?
os.stat doesn't compare anything, it just returns info about a single
file or directory.
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Re: Opposite of split
On 8/16/2010 12:44 PM, Alex van der Spek wrote:
Anybody catches any other ways to improve my program (attached), you are
most welcome.
1. You don't need to separate out special characters (TABs, NEWLINEs,
etc.) in a string. So:
bt='-999.25'+'\t''-999.25'+'\t''-999.25'+'\t''-999.25'+'\t'+'-999.25'
... can be ...
bt='-999.25\t-999.25\t-999.25\t-999.25\t-999.25'
BTW, I think you made a couple of lucky errors in this statement.
Where there are two consecutive apostrophe (') characters, did you mean
to put a plus sign in between? Your statement is valid because the
Python interpreter concatenates strings for you:
x = 'foo''bar'
x == 'foobar'
True
x = 'foo' 'bar'
x == 'foobar'
True
2. Take a look at the functions in the os.path module:
http://docs.python.org/library/os.path.html
These functions might simplify your pathname manipulations. (I didn't
look closely enough to know for sure.)
3. An alternative to:
alf.write(tp+'\t'+vf+'\t'+vq+'\t'+al+'\t'+bt+'\t'+vs+'\n')
... is ...
alf.write(\t.join((tp, vf, vq, al, bt, vs)) + \n)
4. I suggest using a helper function to bring that super-long
column-heading line (alf.write('Timestamp ...) under control:
def multi_field_names(base_name, count, sep_string):
names = [base_name + + str(i) for i in range(1, count+1)]
return sep_string.join(names)
HTH,
John
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Re: Simple Problem but tough for me if i want it in linear time
On Sun, 2010-08-15 at 15:14 +0200, Peter Otten wrote:
ChrisChia wrote:
dataList = [a, b, c, ...]
where a, b, c are objects of a Class X.
In Class X, it contains self.name and self.number
If i wish to test whether a number (let's say 100) appears in one of
the object, and return that object,
is that only fast way of solving this problem without iterating
through every object to see the number value?
dataList.__contains__ can only check my object instance name...
anyone can solve this in linear complexity?
Well, iteration as in
next(item for item in dataList if item.number == 100)
is O(n) and list.__contains__() has no magic way to do better. If you need
O(1) lookup you can use a dict or collections.defaultdict that maps
item.number to a list (or set) of X instances:
lookup = {}
for item in dataList:
lookup.setdefault(item.number, []).append(item)
print lookup[100]
Peter
How about
[obj for obj in dataList if obj.number == 100]
That should create a list of all objects whose .number is 100. No need
to cycle through a loop. If .number doesn't repeat get your object at
index 0. The approach may seem inefficient for the purpose of extracting
a single item, but the list needs to be gone through in any case and the
list comprehension is surely the most efficient way to do it.
Frederic
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