Re: Changing variable to integer
vertigo wrote:
> > Perhaps you meant something more along the lines of this:
> >
> >>>> def PrintWordCountFloat(words):
> > number = 0
> > for index, word in enumerate(words):
> > print "%s %f" % (index, word)
> > number = number + 1
> > print "Total words: %d" %(number)
> >>>> PrintWordCountFloat(range(10))
> > 0 0.00
> > 1 1.00
> > 2 2.00
> > 3 3.00
> > 4 4.00
> > 5 5.00
> > 6 6.00
> > 7 7.00
> > 8 8.00
> > 9 9.00
> > Total words: 10
> >
> > Or similar; I can't read your mind. Just know that enumerate(iterable)
> > yields (index, value) for each item in iterable.
>
>
> sorry, i was not precise. words is a dictionary.
> 1. How can i show it's all variable (with key and value) ?
> 2. How can i show sorted dictionary (by key) ?
> 3. Is there any function which could do fast iteration on elements of
> sorted dictionary ?
>
> Thanx
I hope this helps a bit:
>>> words = {"help":20, "copyright":25, "credits":35}
# show dictionary
>>> for w, s in words.iteritems(): print w, s
...
credits 35
help 20
copyright 25
# show sorted dictionary
# dicts are not ordered, so you have to sort them.
>>> for w, s in sorted(words.iteritems()): print w, s
...
copyright 25
credits 35
help 20
--
Juho Schultz
--
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Re: I think Python is a OO and lite version of matlab
Allen wrote: > Does anyone agree with me? > If you have used Matlab, welcome to discuss it. Matlab is a tool for scientists and engineers. Python is a tool for programmers. I think you are looking at Python from the scientist perspective. Python's numpy and matplotlib modules would probably feel familiar to anyone with some matlab experience. But these are not a part of the language - it is not even a part of the standard library. I will not go deep into the programmer perspective. Some more programmer tools: Java, Tcl, Perl, PHP, Lisp, Ruby. Comparing Python to these makes sense. I think comparing Matlab to any of those would be absurd. Have a look at modpython.org - is there a need for a similar modmatlab? Now, back to the scientist perspective. In 1999, I was starting my M.Sc. in astrophysics and had to select my data analysis tools. I needed the standard scientific tools: scripting, numerics, graphics - Matlab + shell is good enough for this. But I also needed a library for FITS file processing, which was not available in Matlab. So Matlab alone was not enough. Matlab + IRAF + shell was one alternative. Shell + IDL (Interactive Data Language) was another. There were also other possibilities (Fortran for numerics, C or Ftools for FITS). To cut it short, after a while I ended up with shell + IDL as my main tools, occasionally using the others. About two years later my scripts were so complex I decided to learn a scripting language. I was lucky enough to choose Python. Soon I found pyraf, pyfits and numarray, later gnuPlot.py and matplotlib - IDL was no longer needed. Python was enough. Then one day I was looking for a postdoc position. I found something else, and now I do text mining. I still need the science tools: scripting, numerics, graphics. I also need: 1) Regular expressions 2) XML library 3) Database interface Python covers it all. I think Matlab has a Database interface, but how about the others? -- Juho Schultz -- http://mail.python.org/mailman/listinfo/python-list
Re: question about function not executing
Hint:
Posting only the piece of code causing the problem will give you more
answers...
Ara Kooser wrote:
> Hello all,
>
> I hope I am posting this correctly. I am running Python 2.4.2 on
> Slackware 11.0 using IDLE. I am in the process of learning python so I
> am writing a text adventure game using functions and global variables
> only. I know there is a better way to do this but that is for later.
>
>When I run the python program it works fine until I try to go west
> from my inital start room. I get the room description but no raw_input
> prompt. I just get dumped back to >>> in the python shell. I think I
> am missing something simple. I pasted in the code below. I am using
> gmail so I hope the formatting stays. If not I can send the .py as an
> attachment if needed. Thanks.
>
> Ara
>
Giving the command 'w', you call meadow1()
> elif prompt_o1 == "w":
> meadow1()
> def meadow1():
>
> print
> prompt_meadow1
So you end up here, the meadow1() function returns to the
except ValueError:
and ends then as expected.
>
> def meadow1_desc():
> prompt_meadow1
Same problem would occur in here.
I guess you want to call this:
> def prompt_meadow1():
>
> prompt_m1 = raw_input("Type a command: ").lower()
So write
prompt_meadow1()
instead of
prompt_meadow1
(experiment in python shell and you see the difference.
>>> raw_input
>>> raw_input()
now python waits for your input
For the player, create a class.
class player(object):
def __init__(self):
self.poisoned = False
def take_poison(self):
print 'You are poisoned'
self.poisoned = True
# effects of poison in here:
# take some hitpoints
# maybe reduce some stats
# and so on...
# now, generate a player instance
p = player() # calls __init__
# poison the player
p.take_poison()
--
Juho Schultz
--
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Re: String Replace only if whole word?
Michael Yanowitz wrote:
> Hello:
>
> I am hoping someone knows if there is an easier way to do this or someone
> already implemented something that does this, rather than reinventing the
> wheel:
> I have been using the string.replace(from_string, to_string, len(string))
> to replace names in a file with their IP address.
> For example, I have definitions file, that looks something like:
> 10.1.3.4 LANDING_GEAR
> 20.11.222.4 ALTIMETER_100
> 172.18.50.138 SIB
> 172.18.50.138 LAPTOP
> 172.18.51.32 WIN2000
> 127.0.0.1 LOCALHOST
>
> and I have a text file (a Python script) that has these names in the file.
> In most cases the string.replace() command works great. But there is one
> instance which it fails:
> Suppose I had in the file:
> if (LAPTOP_IS_UP()):
>It would replace the string with:
> if ("172.18.50.138"_IS_UP()):
>
>Is there any easy way to avoid this, only replace if a whole word
> matches?
> I probably need something which determines when a word ends, and I will
> define
> a word as containing only 'A'-'Z','a'-'z','0'-'9','_' . As long as the
> string
> contains more of the word digits after the match, don't replace?
>
> Thanks in advance:
> Michael Yanowitz
You need regular expressions for this. Use the re module.
http://docs.python.org/lib/module-re.html
from the docs:
re.sub(pattern, repl, string[, count])
Return the string obtained by replacing the leftmost non-overlapping
occurrences of pattern in string by the replacement repl.
Your pattern would be "[^A-Za-z0-9_]word[^A-Za-z0-9_]"
[^xy] is approximately not in ('x', 'y')
--
Juho Schultz
--
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Re: Standard Forth versus Python: a case study
John Doty wrote: > The problem: > > I have a bunch of image files in FITS format. For each raster row in > each file, I need to determine the median pixel value and subtract it > from all of the pixels in that row, and then write out the results as > new FITS files. > This may be personal bias... I have spent a few years with FITS files so every time I see 'FITS' I think 'astronomy' - maybe you are doing something else. (Someone wrote he does not know what FITS is - see fits.gsfc.nasa.gov In a nutshell: FITS file is a list of header-data units. Each header is text containing optional keyword-value pairs and reading instructions for the data unit. Usually astronomical image data but it can be anything.) Sounds like subtracting sky background from the frames, though for some reason (speed?) column-wise. You could have a look at either PyRAF (www.stsci.edu/resources/software_hardware/pyraf) or PyMidas (www.eso.org/sampo/pymidas/). Running some semi-official sky-subtraction algorithm would at least give you a good case to test against. You could also check if ftools already does this. I have not used it much, but sometimes it saves huge amounts of coding time. heasarc.gsfc.nasa.gov/docs/software/ftools/ftools_menu.html > This is a real problem I need to solve, not a made-up toy problem. I was > originally thinking of solving it in C (I know where to get the pieces > in that language) Could you tell a bit more of the data? Are you aiming for accuracy, speed or getting as complete time series as possible? (for me, speed has never been an issue) Photometry/astrometry/something else? Is there some trade-off like "get best possible result in X seconds"? -- Juho Schultz -- http://mail.python.org/mailman/listinfo/python-list
Re: user modules
Juho Schultz wrote: > Cameron Walsh wrote: > > Hi, > > > > I'm writing a python program to analyse and export volumetric data. To > > make development and extension easier, and to make it more useful to the > > public when it is released (LGPL), I would like to enable users to place > > their own python files in a "user_extensions" directory. These files > > would implement a common interface in order for the main program to be > > able to read them and execute the necessary code. > > > > My question is what is the best way of implementing this? > > > > I have investigated importing them as modules, but unless the user > > modifies the main program I cannot see how the main program can learn of > > the existence of specific modules. > > > > One simple solution would be a shell script that adds user_extensions > (or whatever) to $PYTHONPATH and then starts your main program. Sorry... I was typing faster than reading or thinking. You could have a __init__.py file within user_extensions with __all__ = ["package1", "package2"] If you want every python file within some directory in here, you can auto-generate the __init__.py file in user_extension before importing. (Or you could have some sort of tester for new .py files detected and only after you are sure it works, add it.) from user_extensions import * would import everything mentioned in __all__. You also have access to their names through user_extensions.__all__ The last step would be to put the modules into a list. After the import, user_ext_list = [eval(elem) for elem in user_extensions.__all__ ] for ext in user_ext_list: ext.initialize() ext.get_tab_window() -- http://mail.python.org/mailman/listinfo/python-list
Re: user modules
Cameron Walsh kirjoitti: > Hi, > > I'm writing a python program to analyse and export volumetric data. To > make development and extension easier, and to make it more useful to the > public when it is released (LGPL), I would like to enable users to place > their own python files in a "user_extensions" directory. These files > would implement a common interface in order for the main program to be > able to read them and execute the necessary code. > > My question is what is the best way of implementing this? > > I have investigated importing them as modules, but unless the user > modifies the main program I cannot see how the main program can learn of > the existence of specific modules. > > For example: > > from user_modules import * > # directory 'user_modules' contains __init__.py allowing this > # From here I would need a list of the imported modules, in order to > # execute a common command on each of them, such as > > for module in imported_modules: > module.initialise() > module.get_tab_window() > > > How do I get from the first bit to the second bit, or is there a better > way of obtaining the functionality I need? > > > --Cameron. Sorry... I was typing faster than reading or thinking. You could have a __init__.py file within user_extensions with __all__ = ["package1", "package2"] If you want every python file within some directory in here, you can auto-generate the __init__.py file in user_extension before importing. (Or you could have some sort of tester for new .py files detected and only after you are sure it works, add it.) from user_extensions import * would import everything mentioned in __all__. You also have access to their names through user_extensions.__all__ The last step would be to put the modules into a list. After the import, user_ext_list = [eval(elem) for elem in user_extensions.__all__ ] for ext in user_ext_list: ext.initialize() ext.get_tab_window() -- http://mail.python.org/mailman/listinfo/python-list
Re: user modules
Cameron Walsh wrote: > Hi, > > I'm writing a python program to analyse and export volumetric data. To > make development and extension easier, and to make it more useful to the > public when it is released (LGPL), I would like to enable users to place > their own python files in a "user_extensions" directory. These files > would implement a common interface in order for the main program to be > able to read them and execute the necessary code. > > My question is what is the best way of implementing this? > > I have investigated importing them as modules, but unless the user > modifies the main program I cannot see how the main program can learn of > the existence of specific modules. > One simple solution would be a shell script that adds user_extensions (or whatever) to $PYTHONPATH and then starts your main program. -- http://mail.python.org/mailman/listinfo/python-list
Re: Comment on this script. Possible error in communication with list arg between functions
Phoe6 wrote:
> Hi all,
> Part of my script is to check for pre-requisite rpms to be
> installed.
> If its installed, I just display the rpm version as in rpm database,
> otherwise I output a message saying:
> ' rpm is not installed' and collect the rpm name in a list
> (notInstalled).
> At the end if the len(notInstalled) is greater than 0 then I display
> them all asking it to be installed and exit the program.
> My Script is below:
> ---
> def checkForRpm(rpmname):
> ''' Check for the presence of the RPM. '''
> cin,cout,cerr = os.popen3('rpm -q ' + rpmname)
> output = cout.read()
> global notInstalled
> if len(output) <= 0:
> print rpmname + ' not installed.'
> notInstalled.append(rpmname)
> else:
> print output
>
>
>
> def preReqCheckRpms():
> ''' Check for the required RPMS '''
> listOfRpms = ['firefox','senthil',]
>
>
> for eachRpm in listOfRpms:
> checkForRpm(eachRpm)
> global notInstalled
> if len(notInstalled) > 0:
> print 'The following RPMS are not installed:'
> for eachRpm in notInstalled:
> print eachRpm
> print 'Please install them for the installation to
> continue.'
> sys.exit(-1)
>
> * This is NOT Working.
> * notInstalled.append(rpmname) is not taking effect in
> checkForRpm(rpmname)
> * I dont know how to communicate the notInstalled list to
> preReqCheckRpms.
>
> --
> Senthil
I think return values should be used for communication between
functions. Maybe something like this could work for you (not tested).
def checkForRpm(rpmname):
#
# Strings with 0 lenght are False
if output:
print output
else:
print rpmname + ' is not installed'
return output
def checkPreReqs():
missingRpms = []
for requiredRpm in listOfRpms:
if not checkForRpm(requiredRpm):
missingRpms.append(requiredRpm)
# you could also do this by a list comprehension
missingRpms = [reqRpm for reqRpm in listOfRpms if not
checkForRpm(reqRpm)]
# or you could use the builtin function filter() - see
filter.__doc__ for that
# now, list of lenght 0 is False.
if missingRpms:
# print error messages, exit.
--
Juho Schultz
--
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Re: building lists of dictionaries
Tim Chase wrote:
> parinfo = [{'value':0., 'fixed':0, 'limited':[0,0],
> 'limits':[0.,0.]}.copy() for i in xrange(0,6)]
>
> However, this will still reference internal lists that have
> been referenced multiple times, such that
>
> >>> parinfo[5]['limited']
> [0, 0]
> >>> parinfo[4]['limited'][0] = 2
> >>> parinfo[5]['limited']
> [2, 0]
>
Interesting. Cut-and-paste to my python prompt and I get
>>> parinfo[5]['limited']
[0, 0]
Tried both Python 2.4.1 and 2.5 beta, Linux, GCC 4.0.2
--
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Re: building lists of dictionaries
Jean_Francois Moulin wrote:
> Hi all,
>
> I tried this piece of code (FWIW, it was taken as is from a help section of
> mpfit, a mathematical routine for least square fitting):
>
> parinfo = [{'value':0., 'fixed':0, 'limited':[0,0], 'limits':[0.,0.]}]*6
> The first line builds a list of six dictionaries with initialised keys.
> This is not so!
> I end up with all dictionaries being identical and having their 'fixed' key
> set to 1, and limited[0]==1 and limits[0]==50.
>
> I do not understand this behaviour...
>
> Thanks for helping a newbie.
>
> JF
xvec = [{'value':0}]*6
xids = [id(x) for x in xvec]
print xids
Should print a list of six integers, all equal.
So all elements in your list are the same.
Another way to construct the desired list:
yvec = [{'value':0} for i in range(6)]
yids = [id(y) for y in yvec]
print yids
The elements in this list should be all different.
--
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Re: RegEx conditional search and replace
Martin Evans wrote:
> Sorry, yet another REGEX question. I've been struggling with trying to get
> a regular expression to do the following example in Python:
>
> Search and replace all instances of "sleeping" with "dead".
>
> This parrot is sleeping. Really, it is sleeping.
> to
> This parrot is dead. Really, it is dead.
>
>
> But not if part of a link or inside a link:
>
> This parrot is sleeping. Really, it
> is sleeping.
> to
> This parrot is sleeping. Really, it
> is dead.
>
>
> This is the full extent of the "html" that would be seen in the text, the
> rest of the page has already been processed. Luckily I can rely on the
> formating always being consistent with the above example (the url will
> normally by much longer in reality though). There may though be more than
> one link present.
>
> I'm hoping to use this to implement the automatic addition of links to other
> areas of a website based on keywords found in the text.
>
> I'm guessing this is a bit too much to ask for regex. If this is the case,
> I'll add some more manual Python parsing to the string, but was hoping to
> use it to learn more about regex.
>
> Any pointers would be appreciated.
>
> Martin
What you want is:
re.sub(regex, replacement, instring)
The replacement can be a function. So use a function.
def sleeping_to_dead(inmatch):
instr = inmatch.group(0)
if needsfixing(instr):
return instr.replace('sleeping','dead')
else:
return instr
as for the regex, something like
(]*()?
could be a start. It is probaly better to use the regex to recognize
the links as you might have something like
sleeping.sleeping/sleeping/sleeping.html in your urls. Also you
probably want to do many fixes, so you can put them all within the same
replacer function.
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Re: converting file formats to txt
Steven D'Aprano wrote: > On Tue, 04 Jul 2006 06:32:13 -0700, Gaurav Agarwal wrote: > > > Hi, > > > > I wanted a script that can convert any file format (RTF/DOC/HTML/PDF/PS > > etc) to text format. > > PDF is (I believe) a compressed, binary format of PS. Perhaps you should > look at the program pdf2ps -- maybe it will help. > > > -- > Steven. Or try the program pdftotext? -- Juho Schultz -- http://mail.python.org/mailman/listinfo/python-list
Re: print shell output in a file
Juergen Huber wrote: > hello, > > one more question i will have! > > now i have written a little programm, which delivers me an output on the > shell! > > > Is there a way to put this output in an file?!?! i searched about 2h for > this, but i couldn`t find an answer! > > thnks, juergen Others have suggested creating a file. You could also let the shell to do the work. If you run the program "normally", output goes to screen: python myprog.py Run and redirect the output to a file: python myprog.py > output_of_myprog.txt This also makes controlling the output filename much easier. You could find the following useful: http://www.swc.scipy.org/lec/shell01.html -- http://mail.python.org/mailman/listinfo/python-list
Re: break the loop in one object and then return
Alex Pavluck wrote:
> I am trying to write the following code to block up evaluation and
> prompting for entering new information. However, when I break the loop
> in one object and then return it does not start at the beginning again
> but rather at the point where it exited. Can someone look at the
> following code and give me some feedback.
>
If you want a loop, write a loop.
eval() is a built-in function. Better leave the names of builtins as
they are.
>
> yournum = input("I am thinking of a number between 1 and 100.\n Guess
> which number: ")
> mynum = (yournum-5)
>
If the users first guess is 2, mynum becomes -3...
Better use this - to ensure 100 >= mynum >= 1, and the user can guess
right on 1st try.
import random
mynum = random.randint(1,100)
input evaluates a user-supplied string, and is a bit dangerous.
(Run your original program, and give "mynum" as your second guess.)
So use yournum = int(raw_input("I am thinking...
you could use one while loop instead of two functions and one global
variable.
while (yournum != mynum):
if yournum < mynum:
print "Too low."
else:
print "Too high."
yournum = int(raw_input("Guess again:"))
print "You got it!"
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Re: File Permissions
VJ wrote: > Hi All > > Basically i want to write into a file .If the permissions are not there > then print a error message. > How do i achive this ??? > > Thanks, > VJ > One way would be a try-except block, and leave the permission checking error message generation, etc. to the operating system. try: outfile = file(outfilename,"w") except IOError, errormsg print "Could not write to file %s: %s" % (outfilename, errormsg) -- http://mail.python.org/mailman/listinfo/python-list
Re: Why python doesn't use syntax like function(,,x) for default parameters?
Antoon Pardon wrote: > Op 2006-03-10, Roy Smith schreef <[EMAIL PROTECTED]>: > >>"Dmitry Anikin" <[EMAIL PROTECTED]> wrote: >> >>>There are often situations when a function has independent >>>parameters, all having reasonable defaults, and I want to >>>provide just several of them. In fact, I can do it using >>>keyword parameters, but it's rather long and you have to >>>remember/lookup names of parameters. >> >>Specifying the names of the keyword parameters costs you a little typing >>once, but saves everybody (including yourself) a lot of grief later when >>you're trying to figure out what the heck your code does 6 months later. > > > Could you explain what is so hard in figuring out: > > func(,,4) > Your func has only three parameters, and only one non-default. I think "all have reasonable defaults, I want to provide several" means you might end up with bugs like this. func(,,,1.2e-3,7.6e18,3.124576,3567.0,) func(,,1.24e3,1,21.26e4,,,1220,57,35,0) # bug TypeError: func() takes exactly 8 arguments (9 given) Now what are the correct arguments? 1220.57, 35,and 0 1220,57.35, and 0 1220,57,and 35.0 With keywords parameters, this is easy to answer. func(y=1.2e-3, z=7.6e18, i=3.124576, j=3567.0) func(x=1.24e3, y=1, z=21.26e4, j=1220, k=57,35, w=0) # bug SyntaxError: non-keyword arg after keyword arg. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python Evangelism
Magnus Lycka wrote:
> rtilley wrote:
>
>>
>> I think it's the name. Python. Let's change it to something nicer.
>> Think about it... if you found a Ruby, you'd pick it up and put it in
>> your pocket. If you ran across a Python, you'd run away.
>
>
> I think you have a point, but I also think it's a bit
> late to change it after 15 years or so, considering all
> books, web sites etc. We're stuck with Python, and can
> only do the best of that. Actually, in Swedish, "Jag
> mår pyton" i.e. "I feel like python" means "I feel
> sick", and "det luktar pyton" i.e. "it smells python",
> means "it stinks". That doesn't make Python easier to
> sell here... Still to late to change...
>
In Finnish "ajaa käärme pyssyyn" ("force a snake into a rifle") means
doing something almost impossible. If you have to put a snake into a
rifle, try Python - a bite does not kill you. So it works both ways.
> I think a good example on the problem with letting
> techies like us do naming is that grand successor
> of Unix developed by the great minds at Bell Labs.
>
> First, they name it after a movie which is famous
> for being exceptionally bad--Plan 9 (from outer space).
> Really grand company there!
>
> Then, when they make a real product of it, they call
> it Inferno, and some part of it gets called Limbo.
>
"Inferno - the Lamborghini Diablo of operating systems"
What is the problem here?
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Re: implementation of "complex" type
Russ wrote: > I tried the following: > > x = complex(4) y = x y *= 2 print x, y > > (4+0j) (8+0j) > > But when I tried the same thing with my own class in place of > "complex" above, I found that both x and y were doubled. I'd like to > make my class behave like the "complex" class. Can someone tell me the > trick? Also, where can I find the code for for the "complex" class? I > hope it's written in Python! Thanks. > This is like the difference of tuples and lists. Your own class is mutable. y=x # Names x and y are now bound to the same object. y*=2 # change the object bound to names x and y. Builtin complex is immutable, so you can not manipulate the contents. y*=2 # creates a new object (value = 2*y), binds it to name y. -- http://mail.python.org/mailman/listinfo/python-list
Re: What version of python is running a script
Fernando Rodríguez wrote: > > Hi, > > How can my script tell which version of python is running it? > > Thanks > > import sys # examine these variables sys.version_info sys.version -- http://mail.python.org/mailman/listinfo/python-list
Re: Getting File Permissions
Hari wrote: > Hi, > For getting permissions of a file, the following script has been > suggested in the same group > > import os, stat > st = os.stat(myfile) > mode = st[stat.ST_MODE] > print "mode is", octal(mode & 0777) > > But while executing I am getting error message as follows > > Traceback (most recent call last): > File "", line 1, in ? > NameError: name 'octal' is not defined > > Since I am new to python, can any one help me to solve this error? > A bunch of thanks in advance. > > Hari > You can use "oct" instead of "octal". -- http://mail.python.org/mailman/listinfo/python-list
Re: Vectorization and Numeric (Newbie)
Ronny Mandal wrote: > Assume you have a mathematical function, e.g. f(x) = x + 4 > > To calculate all the values from 1 to n, a loop is one alternative. > Numeric and friends (numarray,numpy) have something like numarray.arange - they return arrays similar to the lists returned by standard libs range function. I would recommend using the built-in array operations as much as possible - in most cases they are much faster than looping, and your code remains simpler. > But to make this function work with vectors instead i.e > f(x_vector) = result_vector, > how should the function then be implemented? > In most numeric libraries, vectors and scalars can be added etc. For the simple f(x) case you can use just the simplest approach: def f(x): return x+4 and call this with scalar and vector args. f_pi = f(3.14159265) f_1to200 = f(numarray.arange(1,200)) -- http://mail.python.org/mailman/listinfo/python-list
Re: How to run shell commands within python
fileexit wrote: > How can I execute shell commands from within python. Specifically, I > am looking for something like the shell "cat". But this also made me > wonder how to execute shell commands anyway, just if i needed to do > that in the future. > You can use os.system() for that. -- http://mail.python.org/mailman/listinfo/python-list
Re: a numarray question
[EMAIL PROTECTED] wrote: > hello everyone > > would anyone please tell me what is the best (fastest) way of replacing > values in numarray arrays? > > lets say i have an array that may contain 0s, and i just want to get > rid of those 0s by replacing them with another number. what would be > the most efficient way to do that? > > many thanks in advance! > One way to do that is data2 = numarray.choose(numarray.equal(data,0), (data, another_number)) I am not sure this is the most efficient way. If you get other suggestions, you can compare them with the timeit module. http://www.python.org/doc/2.4.2/lib/module-timeit.html But if you plan to do calculations with the data, I think replacing zeros is not critical for performance. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python advocacy in scientific computation
Michael Tobis wrote: > Someone asked me to write a brief essay regarding the value-add > proposition for Python in the Fortran community. Slightly modified to > remove a few climatology-related specifics, here it is. > Thank you - this was very good reading. > I would welcome comments and corrections, and would be happy to > contribute some version of this to the Python website if it is of > interest. > A slight broadening of the perspective could show another advantage: Python is also used for data processing, at least in astronomy. Modeling and processing the data in the same environment is very practical. Spend more time on modeling and processing the critical data sections - critical data section may depend on model parameters and sampling (which is often incomplete and uneven). You also avoid wasting CPU cycles to model things not in the data. A theorist may be perfectly happy with Fortran, and an observer could do his stuff with simple scripts. But if they need to work together, Python is a very good option. -- http://mail.python.org/mailman/listinfo/python-list
Re: Too Many if Statements?
Steven D'Aprano wrote: > On Fri, 10 Feb 2006 06:50:25 -0800, slogging_away wrote: > > >>Excellent suggestion, (behold the power of the command line!). I ran >>two saved versions of the script that had produced the symptom >>originally described. The fist seemed to be caused by too many 'if' >>statements, the second by adding another array, but both came up with >>the same system error at the command prompt level shown here: >> >>SystemError: com_backpatch: offset too large > > > Is this a Python error or a shell error? > > If it is a Python error, perhaps you would like to post the entire > traceback? > > > I would believe CamelCaseErrorMessages are produced by Python. The message is exactly the same I reported with the 2500 elifs. I fooled around a bit with this, and it seems that also for/while blocks containing more than ~4860 lines give this error. slogging_away claims his script is about 4900 lines, most of that in a for loop, so my bet is he has trouble with the same bug. -- http://mail.python.org/mailman/listinfo/python-list
Re: Determining an operating system's default browser
John McMonagle wrote:
> Is there a python module which can determine an operating system's
> default web browser application.
>
> I would like to use it in the following context: I have a GUI
> application where all the documentation is written as html pages. I
> wish to have these html help pages open in the default browser when
> selected from the application's Help menu
>
> If python can determine the path to the default browser, I can then just
> spawn it.
>
> Regards,
>
> John McMonagle
>
>
>
I think the htmlview command is used for this purpose (displaying html
documentation of applications) on many Linuxes. So you could try
os.system('htmlview'). Given the variety of Unixes (and even Linuxes)
out there this is not a general solution.
So I would try htmlview first. If it does not work, the program could
ask the user for his favourite browser the 1st time he looks at docs,
and save this to a configuration file.
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Re: line wrapping problem
ZeD wrote: > Ciao, Juho Schultz! Che stavi dicendo? > Moro, ZeD! Kunhan pulisen. Should we stick to English? > >>should work. IMO file.write() is self-explanatory but "print >> file" is >>a bit obscure. > > is obscure only if you have never used a shell :) > (I have used the shell a bit. I started using Linux at work when 2.2 series kernels did not exist.) Assume a newbie plays around with a piece code. If the code has f.write(x) or print >> f,x - in which case the newbie is more likely to break the code by rebinding f to something non-file? And in which case he will more likely understand the error message, something like "f has no write attribute"? I am sure the >> can be useful - it is quick to add after a simple print when you want less chatter and more logfiles. But IMO it is not self-documenting. Having to very different uses for an operator in the same language is sort of confusing. -- http://mail.python.org/mailman/listinfo/python-list
Re: line wrapping problem
S Borg wrote:
> Hello,
>
> I am parsing text from one document to another. I have a scheme
> similar to:
>
> for x in myfoobar:
>print >> mytextfile, "%s" % mydictionary[x], #all on same line
> print >> mytextfile, '\n' #new line
>
>
> I am getting line breaks before my explicit line break. Am I
> unwittingly copying '\n' characters from the original file?
> How should I fix this(What is the 'Pythonic' solution)?
>
> thanks,
> -S
>
mytextfile.write("%s" % mydictionary[x])
should work. IMO file.write() is self-explanatory but "print >> file" is
a bit obscure.
--
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Re: Too Many if Statements?
Bryan Olson wrote:
> Alan Morgan wrote:
>
>> slogging_away wrote:
>>
>>> Hi - I'm running Python 2.4.2 (#67, Sep 28 2005, 12:41:11) [MSC v.1310
>>> 32 bit (Intel)] on win32, and have a script that makes numerous checks
>>> on text files, (configuration files), so discrepancies can be reported.
>>> The script works fine but it appears that I may have hit a wall with
>>> 'if' statements.
>>>
>>> Due to the number of checks perfromed by the script on the text files,
>>> (over 500), there are quite a few 'if' statements in the script, (over
>>> 1150). It seems that it is at the point that when I add any additional
>>> 'if' statements the script will not run. No error is produced - it
>>> just returns to the python prompt much the same as when a successful
>>> 'Check Module' command is selected. If I delete some other 'if'
>>> statements the new ones work so it appears that it has hit a limit on
>>> the number of 'if' statements. This has stunted any further checks for
>>> the script to make on the text files.
>>>
>>> Hs anyone ever run into this sort of thing?
>>
>>
>>
>> I generated files with 1, 25000, and 5 simple if statements
>> and ran
>> them. 1 was okay, 25000 gave a bizarre internal error, and 5
>> segfaulted
>> and died. My system has plenty of memory and it isn't obvious to me
>> why python
>> should be so bothered about this. I'm not sure why I can have 10x the
>> number of
>> if statements that cause you trouble. There might be some overall
>> limitation
>> on the number of statements in a file.
>
>
> I made a script with 100,000 if's, (code below) and it appears
> to work on a couple systems, including Python 2.4.2 on Win32-XP.
> So at first cut, it doesn't seem to be just the if-count that
> triggers the bug.
I tried that code. It runs fine.
However, the following gives a SystemError with only 2500 elif's.
#!/usr/bin/env python
lines = [ 'n = -1','m = 0','if n < 0:',' m = 2*n',]
for i in range(2500):
lines.append('elif n == %i:' % i)
lines.append('m = 2*n')
prog = '\n'.join(lines)
progfile = file('if.py','w')
progfile.writelines(prog)
progfile.close()
exec prog
Traceback (most recent call last):
File "iftest.py", line 10, in ?
exec prog
SystemError: com_backpatch: offset too large
I tried this with Python 2.3.3 and 2.3.4 (Linux) and both fail.
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Re: how to copy a Python object
[EMAIL PROTECTED] wrote: > Already thanks for the reply, > > but how to write your own copy operator? Won't you always be passing > referrences to new_obj? > If you need to modify the behaviour of copy or deepcopy, you can give your class __copy__ and __deepcopy__ methods. Then copy.copy and copy.deepcopy will use these. As a silly example, you could use: def __copy__(self): raise IOError, 'Permission denied.' http://www.python.org/doc/2.4.2/lib/module-copy.html -- http://mail.python.org/mailman/listinfo/python-list
Re: problems writing tuple to log file
[EMAIL PROTECTED] wrote:
> i am having a problem writing a tuple to a text file. my code is
> below.
>
> what i end up getting is a text file that looks like this
>
> burger, 7up
> burger, 7up
> burger, 7up
>
> and this is instead of getting a list that should look like this
>
> burger, 7up
> fries ,coke
> cake ,milk
>
> note that i have print statements that print out the results of the
> scraping and they are fine. they print out burger, fries, cake and
> then 7up, coke, milk
>
> however there is something faulty in my writing of the tuple to the
> text file. perhaps related to the indentation that causes it to write
> the same stuff over and over?
>
>
>
> for row in bs('div'):
What kind of function is 'bs'? Should you use 'row'
(which you are looping over) inside the loop?
Seems that your code is equal to
for row in range(len(bs('div'))):
> for incident in bs('span'):
Just like you use 'incident' here, inside the other loop.
> foodlist = []
> b = incident.findPrevious('b')
> for oText in b.fetchText( oRE):
> #foodlist.append(oText.strip() + "',")
> foodlist += oText.strip() + "','"
> food = ''.join(foodlist)
> print food
>
After "print food" you repeat the loop, overwriting "food" until last
round. And after you have found the last "food", you put it in "tuple".
> tuple = (food + drink "\n")
A tip: 'tuple' is a built-in function, just like 'open' you use.
This statement overwrites that function with a string.
It is usually a good idea to leave the built-ins as they are,
and use some other names for variables.
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Re: beta.python.org content
Steve Holden wrote: > How does > > http://beta.python.org/about/beginners/ > > look? > > regards > Steve I think the content is good, but I would suggest putting some bullet points with links at the top. IMO top part of the beginner page should somehow indicate that tutorial and FAQ is accessible from this page. The page looks a bit dull - there is nothing bright-colored there. Have a look at the www.holdenweb.com in your sig to see what I mean. The small lines of red and yellow on the upper right and the orange picture on used there makes the page a lot more alive. -- http://mail.python.org/mailman/listinfo/python-list
Nitpicking - slightly misleading traceback
if ((data[x][y] > 0) or (datadict.has_key[key])): Traceback (most recent call last): File "reduce.py", line 524, in remove_badvalues if ((data[x][y] > 0) or TypeError: unsubscriptable object However, the bug sits on the next line. I used square brackets when normal brackets were needed - should have written datadict.has_key(key) as the old code had datadict[key]. In the real code variable names are so long that I must split the line. I feel the traceback is misleading. I guess the best solution is to write code without bugs... -- http://mail.python.org/mailman/listinfo/python-list
Re: append to the end of a dictionary
Yves Glodt wrote:
> Hi there,
>
> I seem to be unable to find a way to appends more keys/values to the end
> of a dictionary... how can I do that?
>
> E.g:
>
> mydict = {'a':'1'}
>
> I need to append 'b':'2' to it to have:
>
> mydict = {'a':'1','b':'2'}
>
mydict['b'] = '2'
--
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Re: Using non-ascii symbols
Christoph Zwerschke wrote: > "These operators ≤ ≥ ≠ should be added to the language having the > following meaning: > > <= >= != > > this should improve readibility (and make language more accessible to > beginners). > I assume most python beginners know some other programming language, and are familiar with the >= and friends. Those learning python as their first programming language will benefit from learning the >= when they learn a new language. Unicode is not yet supported everywhere, so some editors/terminals might display the suggested one-char operators as something else, effectively "guess what operator I was thinking". Fortran 90 allowed >, >= instead of .GT., .GE. of Fortran 77. But F90 uses ! as comment symbol and therefore need /= instead of != for inequality. I guess just because they wanted. However, it is one more needless detail to remember. Same with the suggested operators. -- http://mail.python.org/mailman/listinfo/python-list
Re: OT: excellent book on information theory
Bengt Richter wrote: > On Thu, 19 Jan 2006 14:12:24 +0200, Juho Schultz <[EMAIL PROTECTED]> wrote: > >>Last month I spent about an hour trying to explain why >>a*2.5e-8 = x >>raises a SyntaxError and why it should be written >>x = a*2.5e-8 >>The guy who wrote the 1st line has MSc in Physics from Cambridge (UK). >>In mathematics, there is no difference between the two lines. > > > ISTM probable that his original equation was really saying > assert a*2.5e-8 == x > which is not very different from > assert x == a*2.5e-8 > > Did you mention that "=" is not "==" in python? > I too would resist the idea that > assert a*2.5e-8 == x > "should be written as" > x = a*2.5e-8 > > Regards, > Bengt Richter He tried to assing 2.5e-8 times value of variable a to variable x. It had nothing to do with testing equality or asserting. It is just that he had absolutely no programming skills at all. However, he is learning quite fast. -- http://mail.python.org/mailman/listinfo/python-list
Re: OT: excellent book on information theory
Anton Vredegoor wrote: > > Returning to the original book, why did they write a lot of it (at > least the first few pages until I gave up, after having trouble > understanding formulas about concepts I have no such trouble with when > framed in less jargonized from) in unintelligible mathemathical > notation when there's Python? > Because the intended audience is probably reads formulas better than they read Python. The 1st sentence of the Introduction: "This book is aimed at senior undergraduates and graduate students in Engineering, Science, Mathematics and Computing". Last month I spent about an hour trying to explain why a*2.5e-8 = x raises a SyntaxError and why it should be written x = a*2.5e-8 The guy who wrote the 1st line has MSc in Physics from Cambridge (UK). In mathematics, there is no difference between the two lines. > I prefer a nice Python function over some strange latech symbols. If > not Python there's always pseudo code or good old natural language. > Don't tell me those math formulas are what it 'really' is, or even that > it's more precise that way. The old trick of 'but there are some things > that cannot be expressed in any other way than by using formulas' > doesn't get one many optimization points in my world. > > Anton > -- http://mail.python.org/mailman/listinfo/python-list
Re: Find and slice problem
[EMAIL PROTECTED] wrote: > Hi guys, been going around in circles with this so I hope you can help! > > My current situation is I'm using Grinder and Jython to test pages, but > the log on process is giving me some headaches. After entering the > correct username and password, you then need to enter 3 characters from > the security phrase. I'm attempting to read the HTML to find out with > characters I need (e.g. 1st, 3rd and 6th char) then look up those > values in the security phrase, but I'm getting stuck on the following > function: > > > > def getValue(page,delimEnd) : > EndVar = page.find(delimEnd) > thisVar = page[EndVar-1:EndVar] > return thisVar > > > > What I'm attemping to pass in is some multiline HTML(above) and pick up > the proceeding character, but it seems to be reading from the end of > the HTML instead! page.find(delimEnd) returns -1 if delimEnd is not found, and after that you take page[-2:-1], i.e. second last character. So you could add a test for that, if EndVar == -1 etc. but I recommend using page.index(delimEnd) which raises an error if delimEnd is not found. -- http://mail.python.org/mailman/listinfo/python-list
Re: how do "real" python programmers work?
bblais wrote: > In Python, there seems to be a couple ways of doing things. I could > write it in one window, and from a Unix shell call >python myscript.py > and be like C++, but then I lose the interactiveness which makes > prototyping easier. If I use the python shell, I can use import (and > reload), or execfile perhaps. > > How do experienced python programmers usually do it? Is there a > "usually" about it, or is it up to personal taste? Are there any > convenient ways of doing these things? > Disclaimer: I do not consider myself "an experienced python programmer". For scripts and small programs (one file, one developer) I use emacs and python shell. For larger projects I use Eclipse and pydev. -- http://mail.python.org/mailman/listinfo/python-list
Re: how to improve this simple block of code
py wrote:
> Say I have...
> x = "132.00"
>
> but I'd like to display it to be "132" ...dropping the trailing
> zeros...I currently try this
>
> if x.endswith("0"):
> x = x[:len(x)-1]
> if x.endswith("0"):
> x = x[:len(x)-1]
> if x.endswith("."):
> x = x[:len(x)-1]
>
> I do it like this because if
> x = "132.15" ...i dont want to modify it. But if
> x = "132.60" ...I want it to become "132.6"
>
> is there a better way to do this? It seems a bit ugly to me.
>
> T.I.A
> (thanks in advance)
>
x = x.rstrip('0') # removes trailing zeros
x = x.rstrip('.') # removes trailing dot(s)
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Re: Maximum List size (item number) limit?
[EMAIL PROTECTED] wrote: > Juho Schultz > >>NIR_mean_l only from lines 1, 4, 7, ... >>R_mean_l only from lines 2, 5, 8, ... >>G_mean_l only from lines 3, 6, 9, ... > > > This can be the problem, but it can be right too. I guess he is expecting 3000 elements, not 1000, as he wrote: "And I noticed that all the lists that should contain 3000 items, contains less as follows: NIR_mean_l = 1000 items" -- http://mail.python.org/mailman/listinfo/python-list
Re: Maximum List size (item number) limit?
Kriston-Vizi Janos wrote: > Dear Mr. Kern, and Members, > > Thank you very much for the fast answer, my question became > over-simplified. > > My source code is appended below. It uses two text files (L.txt and > GC.txt) as input and merges them. > > Both L.txt and GC.txt contains 3000 rows. When running, the code stops > with error message: > > 'The debugged program raised the exception IndexError "list index out of > range" > File: /home/kvjanos/file.py, Line: 91' > > And I noticed that all the lists that should contain 3000 items, > contains less as follows: > NIR_mean_l = 1000 items > Code that's failing: > # Processing L file > line_no_l =0# Input L file line number > type_l = 1 # Input L file row type: 1 (row n),2 (row n+1) or 3 (row n+2) > # Append L values to lists. > for line in inp_file_l.xreadlines(): > line_no_l = line_no_l + 1 > if line_no_l == 1: # To skip the header row >continue > data_l = [] # An L row > data_l = line.split() > if type_l == 1: >NIR_mean_l.append(data_l[2]) # Append 3rd item of the row to the list >NIR_stdev_l.append(data_l[3]) # Append 4th item of the row to the list >type_l = 2 # Change to row n+1 > else: > if type_l == 2: > R_mean_l.append(data_l[2]) > R_stdev_l.append(data_l[3]) > type_l = 3 > else: > G_mean_l.append(data_l[2]) > G_stdev_l.append(data_l[3]) > area_l.append(data_l[1]) > type_l = 1 > inp_file_l.close() > Looking at the data files, it seems there is no header row to skip. Skipping 1st row seems to cause the discrepancy of vector sizes, which leads to the IndexError. should NIR_mean_l[0] be 203 or 25? As the comments in your code suggest, the code adds values to NIR_mean_l only from lines 1, 4, 7, ... R_mean_l only from lines 2, 5, 8, ... G_mean_l only from lines 3, 6, 9, ... Try with 12 lines of input data and see how the vectors are 4 elements before filtering/writing. -- http://mail.python.org/mailman/listinfo/python-list
Re: Visualisation Engine for Python
rodmc wrote: > I am looking for a 2D data visualisation or graphics library for > Python. Can anyone point me in the right direction? > > > Thanks in advance, > > rod > Two tools I have used are Gnuplot-py http://gnuplot-py.sourceforge.net/ and matplotlib http://matplotlib.sourceforge.net/ -- http://mail.python.org/mailman/listinfo/python-list
Re: os.path.splitext() and case sensitivity
rbt wrote: > Hi, > > Is there a way to make os.path.splitext() case agnostic? > > def remove_file_type(target_dir, file_type): > for root, dirs, files in os.walk(target_dir): > for f in files: > if os.path.splitext(os.path.join(root, f))[1] in file_type: > pass > > remove_file_type(sysroot, ['.tmp', '.TMP']) > > As you can see, the way I do it now, I place file extensions in a list. > However, I'd like to able just to say '.tmp' and for that to work on any > type of file that has tmp (no matter the case) in the extension. > > Many thanks!!! One solution would be to convert the extensions to lowercase (or uppercase, if you prefer that) if fileExtension.lower() == ".tmp": -- http://mail.python.org/mailman/listinfo/python-list
Re: How to check if a string "is" an int?
Neuruss wrote: > Can't we just check if the string has digits? > For example: > > x = '15' if x.isdigit(): > > print int(x)*3 > > > 45 > > No, we can't. '-15' has non-digits but is a valid int. Another point is that the try-except can also be used for string-to-float conversion -- http://mail.python.org/mailman/listinfo/python-list
Re: text manipulation
Johhny wrote:
> Hello,
>
> I am trying to write a script in python (to replace a perl script with
> limited functionality). Now I have some issues. Currently I am using
> the perl to load the file then regex parse certain lines to remove
> characters (uncomment lines and change variables). I would like to take
> that into the python script. I have had a look at the module "string"
> and I dont think its what Im looking for.
>
> Here is an example of some text I would like to manipulate
>
> #comment here
> #user_defined_variable = no
> #
>
> I would like to make that
>
> #comment here
> user_defined_variable = yes
> #
>
> With perl/sed Its very easy, However Im having issues to do it in
> python. Any advice would be great.
>
> Regards,
>
> Johhny.
>
Have you also looked at the built-in string methods?
The following script is probably something you
could start with - it just uncomments lines
and replaces values of some variables.
# dictionary of the variable names
# contains the replacement values
newvalues = {'userdefinedvar1':'yes',
'userdefinedvar2':'123.654.345.234'}
# read file to input
output = []
for line in input:
# check if it is a comment with "="
if line.startswith('#') and ('=' in line):
name, oldvalue = (line.lstrip('#')).split('=')
# line.lstrip removes leading comments,
# split('=') finds the assignment
if newvalues.has_key(name):
# replace line
output.append("%s = %s" % (name, newvalue[name]))
else:
# or just uncomment
output.append("%s = %s" % (name, oldvalue))
else:
output.append(line)
# write output to file
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Re: How to creat a file?
sandorf wrote: > I'm new to python. Have a simple question. > > "open" function can only open an existing file and raise a IOerror when > the given file does not exist. How can I creat a new file then? > You already have two correct answers. A warning: if you open a existing file for writing, it is truncated (the old contents of that file disappear.) For adding new content to the end of an existing file, you can use: f = open(filename,'a') -- http://mail.python.org/mailman/listinfo/python-list
Re: Nested loop
viewcharts wrote:
> I am reading two text files comparing the values in one to the other,
> this requires two loops. The problem is that when the inner loop is
> finished, it never goes back into the loop. Any suggestions?
>
>
> for refSymbol in symbols.readlines():
> for lookupSymbol in myfile.readlines():
> showme = lookupSymbol.split('\t')
> if showme[3] == refSymbol.strip():
> priceNew.write(refSymbol.strip()+" "+showme[10])
>
>
>
When the inner loop is finished for the 1st time,
myfile has been read. So next time you start to the
loop, myfile.readlines() returns an empty list.
Something like this should be better:
lookupSymList = myfile.readlines()
for refSymbol in symbols.readlines():
for lookupSymbol in lookupSymList:
showme = lookupSymbol.split('\t')
if showme[3] == refSymbol.strip():
priceNew.write(refSymbol.strip()+" "+showme[10])
--
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Re: append to non-existing list
Yves Glodt wrote: > Hello, > > if I do this: > > for row in sqlsth: > pkcolumns.append(row[0].strip()) > etc > > > without a prior: > > pkcolumns = []; > > > I get this error on first iteration: > UnboundLocalError: local variable 'pkcolums' referenced before assignment > > I guess that's normal as it's the way python works...?!? > > My question is: Is there no way to append to a non existing list? > > I am lazy for declaring it first, IMHO it bloats the code, and (don't > know if it's good to say that here) where I come from (php) I was used > to not-needing it... > > > regards, > Yves You mean you want to type "pkcolumns" only once to keep your code short? Would something like this be useful? pkcolumns = [row.strip() for row in sqlsth] -- http://mail.python.org/mailman/listinfo/python-list
Re: Cursor Position.
Samantha wrote: > I will be using Tkinter. All I need is a way to get the X,Y position from a > mouse click. I am trying to have an image loaded to click on, but that seems > to be a problem. So if I can just get the position from the screen of a > graphics program, showing an image, it will work for me. > S If you use TkInter, use also these: http://www.pythonware.com/library/tkinter/introduction/index.htm http://infohost.nmt.edu/tcc/help/pubs/tkinter/ For mouse click position, this might be helpful: http://www.pythonware.com/library/tkinter/introduction/events-and-bindings.htm -- http://mail.python.org/mailman/listinfo/python-list
Re: How do I create a dir using Python.
sumi wrote:
> How do i create a dir using python.
>
You could use
os.mkdir("my_dir_name")
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Re: any python module to calculate sin, cos, arctan?
Shi Mu wrote: > any python module to calculate sin, cos, arctan? math There are two versions of arctan: atan and atan2. atan2(y,x) does the quadrant selection you do not get from atan(y/x) -- http://mail.python.org/mailman/listinfo/python-list
Re: Pylab and pyserial plot in real time
[EMAIL PROTECTED] wrote: > Hiya, > > I've got a PIC microcontroller reading me humidity data via rs232, this > is in ASCII format. I can view this data easily using hyperterminal or > pyserial and convert it to its value (relative humidty with ord(input)) > > But what im trying to do is plot the data in real time, ideally with > pylab - as it looks simple to use and simple is the way i want to go! > This might be close to what you are trying to do: import time import pylab # interactive mode on pylab.ion() timefig = pylab.figure(1) timesub = pylab.subplot(111) dt = 0.1 t = pylab.arange(0.0, 2.0, dt) h = 1.2*pylab.sin(t) lines = pylab.plot(t,h) for i in range(8): t = t + dt h = 1.2*pylab.sin(t) lines[0].set_data(t,h) timesub.set_xlim((t[0],t[-1])) pylab.draw() time.sleep(1.0) It shows a piece of sine curve, and updates the x-axis with time. -- http://mail.python.org/mailman/listinfo/python-list
Re: Not Equal to Each Other?
[EMAIL PROTECTED] wrote:
> How do I 'define' set? Is there something to include (like import
> random)?
>
set is a built-in type in Python 2.4
If you use 2.3 you can use the sets module with "import sets"
> while (choice == 3) and len(set(cellboard[0:8]))==len(cellboard[0:8]):
> # DEFINE TWO RANDOM VARIABLES (ONE FOR ARRAY, ONE FOR NUMBER
> VALUE)
> solvingrandom = random.randint(1,9)
> cellboardrandom = random.randint(0,8)
> set(cellboard[0:8])
>
> # CHECK TO MAKE SURE THE RANDOMLY ASSIGNED CELL DOES NOT HAVE A
> VALUE
> if (cellboard[cellboardrandom] is not ('1' or '2' or '3' or '4'
> or '5' or '6' or '7' or '8' or '9')):
> cellboard[cellboardrandom] = solvingrandom
>
> The above is my code (right now it will only work for the first row's
> numbers). Anything else I need to add?
>
Simplify your code a bit:
'2' is not ('1' or '2' or '3' or '4' or '5' or '6' or '7' or '8' or '9')
evaluates to True
'1' is not ('1' or '2' or '3' or '4' or '5' or '6' or '7' or '8' or '9')
evaluates to False
Somehow I do not believe you want that behavipur.
If cellboard contains characters, you could use:
if (cellboard[cellboardrandom] not in '123456789')
for integers, the following should work:
if not (1 <= cellboard[cellboardrandom] <= 9)
Using None to code empty cells, you could even have:
if (cellboard[cellboardrandom] is None)
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Re: * TypeError - Need help passings args
Ernesto wrote: > Thanks, that ran without errors. The only problem now is that it > launches devcon.exe without actually passing the parameters to the > program. It's as if I just typed "devcon" at a Windows command prompt > and pressed enter. I can't figure out why it doesn't accept my > parameter. > I run python 2.3 on Linux os subprocess module and Windows executables are not too familiar to me. But according to docs subprocess.Popen() should accept both list and string arguments. Your strings have backslashes so check docs.python.org/ref/strings.html a = 'disable "@USB\VID_0403&PID_6010&MI_00\7&15E4F68&1&' print a disable "@USB\VID_0403&PID_6010&MI_00&15E4F68&1& \7 is the ASCII bell so your args may be different from what you think. -- http://mail.python.org/mailman/listinfo/python-list
Re: * TypeError - Need help passings args
Ernesto wrote: > My program is below. I'm trying to use two Windows ".exe" files with > my command line python interface. I get user input, then call > "launchWithoutConsole". This was working OK until I introduced the > 'args' part. Now I get the following error everytime I call > "launchWithoutConsole": > > return subprocess.Popen([command] + args, > startupinfo=startupinfo).wait() > > TypeError: can only concatenate list (not "str") to list > > I'm not sure if it's the WAY I'm passing it or if it's the function > itself (which I retrieved from > http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/409002 > ) > > Please help. Thanks! > [command] is a list. So also "args" should be a list, otherwise [command] + args produces an error. Add a few square brackets to the calls, just like in the link. -- http://mail.python.org/mailman/listinfo/python-list
Re: OpenSSL in Python
dcrespo wrote: > Hi to all, > > What do I have to install to get the following code work (Win XP, > Python 2.4.2) > > > from OpenSSL import SSL > import config > > KEY_FILE = config.SSL_KEY_FILE > CERT_FILE = config.SSL_CERT_FILE > > > -- > > I've been looking for OpenSSL for python. I found pyOpenSSL, but it > requires the OpenSSL library, which I only found on > http://www.openssl.org/, but don't know how to install. > Open source is very often distributed as source tarballs that contain installation instructions. So: Download archive - extract - read files named INSTALL, README, ... Repeating the advice you have from some other posters: You have to install both OpenSSL (the library) and pyOpenSSL (so python can use the library). > Other thing is the "config" module... I'm lost. Someone knows? :-S > I'd guess "config" is local module related to your system setup. Nothing with that name comes with Python or pyOpenSSL. > My main purpose is to enable xml-rpc server over an SSL connection. > After installing pyOpenSSL have a look at pyOpenSSL-0.6/examples/SecureXMLRPCServer.py > Thanks > > Daniel > I hope this helped a bit. -- http://mail.python.org/mailman/listinfo/python-list
Re: Jpg
Tuvas wrote:
> I am building a GUI interface at the moment, and would like to have
> support for displaying a jpg file, and a FITS file if possible. Is
> there any way to do this? My interface has been written in Tkinter at
> the moment, especially because of it's great portability, I wouldn't
> have to install the other interface software on every computer that I
> use (At the moment it is 3, and will signifigantly increase). I'd
> prefer to only use built-in functions, but if it can't be done, I'm
> willing to look for something else. Is there any way I can do this?
> Thanks!
>
For FITS file reading, an alternative to pCFITSIO is PyFITS
(http://www.stsci.edu/resources/software_hardware/pyfits).
I guess both need numarray...
gifImage = Tkinter.PhotoImage(file="file.gif")
ima = yourCanvas.create_image(xpos,ypos,image=gifImage)
is the quickest way to display gifs. My version of Tkinter (1.177)
does not directly support jpg, but with PIL that should be possible.
Ugly but quick solution (for Linux): produce gifs from FITS/jpg
files with os.system("convert") and feed them to Tkinter.
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Re: nested escape chars in a shell command
Eli Criffield wrote:
> I'm try run an ssh command in pexpect and I'm having trouble getting
> everything escaped to do what i want.
>
> Here's a striped down script showing what i want to do.
>
> --
> #!/usr/bin/env python
> import pexpect
> import sys
> if len(sys.argv) < 3:
> print "ssh.py host command"
> sys.exit(1)
>
> host = sys.argv[1]
> command = sys.argv[2]
>
> child = pexpect.spawn('''sh -x -c "stty -echo ; ssh -t -o
> 'StrictHostKeyChecking no' %s '%s' |awk '{print \"%s:\"$0}' "
> '''%(host,command,host), timeout=30)
>
> child.setlog(sys.stdout)
> child.expect(pexpect.EOF)
> --
>
> The problem in the pexpect.spawn line, It doesn't like the \"%s:\" part
> of the awk command. This is necessary so i can see what server the
> command is running on, In the full script the command will be running
> on about 100 servers at a time.
> It parses out into:
> + stty -echo
> + ssh -t -o 'StrictHostKeyChecking no' testserver date
> + awk '{print testserver:$0}'
> It totally strips out the "
>
> The stty -echo is required because part of what the program does is it
> tries to remember any passwords that are asked for, So you can run a
> command like "su -c id" and it will remember roots password for the
> next
> server and try that. -echo keeps the root password from being echoed to
> the screen.
>
> The second problem with the command is while "su -c id" works (taking
> out the awk part) running any command with more then one word after the
> -c in su fails, It strips out the '
> like so:
> ./sshexpect testserver "su -c 'ls -l /root'"
> + stty -echo
> + ssh -t -o 'StrictHostKeyChecking no' testserver 'su -c ls' -l /root
> su: user /root does not exist
>
> I have tried every combination of escaping i can think of can i can't
> get either problem solved.
>
> Any ideas?
>
> Eli
>
You can pass the argument list of your command to
pexpect.spawn(comm, args=['arg1','arg2'])
If the argument list is empty, pexpect tries to get the arguments
from the comm you passed to it. I guess this gives you problems.
Try using the args parameter.
Simplest would be args=[' '] just to avoid the processing.
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Re: my array subset method could be improved?
Jim O'D wrote: > Hi all > > I have an array a=array([2,3,1]). > > I want to extract an array with all the elements of a that are less than 0. > > Method 1. > new = array([i for i in a if i < 0]) > > Method 2. > new = a[nonzero(a<0)] > > I'm using Numeric arrays but can't seem to find a function that does this. > > Am I missing a more obvious way to do it quickly? > > Thanks > > Jim new = Numeric.compress(Numeric.less(a,0),a) -- http://mail.python.org/mailman/listinfo/python-list
Re: how to make this code faster
[EMAIL PROTECTED] wrote: > def f(x,y): > return math.sin(x*y) + 8 * x > I have code like this: > > def main(): > n = 2000 > a = zeros((n,n), Float) > xcoor = arange(0,1,1/float(n)) > ycoor = arange(0,1,1/float(n)) > > > for i in range(n): > for j in range(n): > a[i,j] = f(xcoor[i], ycoor[j]) # f(x,y) = sin(x*y) + 8*x > > print a[1000,1000] > pass > > if __name__ == '__main__': > main() > > > I try to make this run faster even using psyco, but I found this still > slow, I tried using java and found it around 8x faster... > I guess the double loop (4E6 rounds) makes your program so slow. I assume you are using numarray or numeric for this. The built-in array operations are a lot faster. Try using them instead. And function calls are not free either. Xcoor and ycoor are equal, so there is no need to generate them both. I guess the following would be a lot faster: def func(): n = 2000 a = numarray.zeros((n,n), "Float") coor = numarray.arange(0,1,1/float(n)) for i in range(n): a[:,i] = numarray.sin(coor*coor[i]) + 8*coor print a[1000,1000] pass -- http://mail.python.org/mailman/listinfo/python-list
Re: recursive function
mg wrote: > Hello, > > In a recursive function like the following : > > > def foo( j ) : > j += 1 > while j < n : j = foo( j ) > return j > > > in found that the recursivity is limited (1000 iterations). Then, I have > two questions : > - why this mecanism has been implemented ? > - it is possible to increase or remove (and how) the number of iterations ? > > Regards, > Mathieu Try the following for answers to both questions: import sys print sys.setrecursionlimit.__doc__ I guess 1000 is the default value. -- http://mail.python.org/mailman/listinfo/python-list
Re: python plotting with greek symbols within labels recommendations?
[EMAIL PROTECTED] wrote:
> hello all,
>
> this message is geared toward those of you in the scientific community.
> i'm looking for a python plotting library that can support rendering
> greek symbols and other various characters on plot axes labels, etc. I
> would prefer something that adheres to tex formatting (as implemented
> in latex, matlab, etc and has the form $\alpha$ to represent the greek
> character alpha for example).
>
> thus far, i've found that matplotlib
> (http://matplotlib.sourceforge.net/) can do this, albeit the
> implementation is so poor that you cannot mix standard text with
> symbols on the same plot element.
>
>
If you already have installed matplotlib, have a look at
matplotlib-0.X.Y/examples/tex_demo.py
It shows you how to mix text and symbols.
The other examples in the directory could also be useful.
Essentially you need to remember
matplotlib.rc('text', usetex=True)
before plotting.
If you need complex stuff (fractions, sums, integrals) try
putting an r before the string: pylab.ylabel(
r"Density $\left(\rho =\frac{x^2+\frac{x+1}{x-1}}{\kappa(x)K_{ij}}\right)")
works fine, at least on my system.
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Re: Background process for ssh port forwarding
Jesse Rosenthal wrote:
> Hello all,
>
> I'm writing a script which will backup data from my machine to a server
> using rsync. It checks to see if I am on the local network. If I am, it
> runs rsync over ssh to 192.168.2.6 using the pexpect module to log in.
> That's the easy part.
>
> Now, when I'm not on the local network, I first want to open up an ssh
> connection to do port forwarding, so something like this:
>
> def hostforward():
> #This is based on the assumption that the passfile is the gnus
> #authinfo file, or has a similar format...
> f = open(PASS_FILE, "r")
> f_list = f.read().split(' ')
> f.close()
> #Now, we get the entry after "password" (be slicker to make it a
> #dictionary, but maybe wouldn't work as well).
> pass_index = f_list.index('password') + 1
> forwardpass = f_list[pass_index]
> #now we connect
> command = 'ssh -l %s -L 2022:%s:22 %s' % \
> (login, my_server, forwarding_server)
> connection = pexpect.spawn(command)
> connection.expect('.*assword:')
> connection.sendline(forwardpass)
>
> If I end this with 'connection.interact()', I will end up logged in to the
> forwarding server. But what I really want is to go on and run rsync to
> localhost port 2022, which will forward to my_server port 22. So, how can
> I put the ssh connection I set up in hostforward() in the background?
> I need to make sure that connection is made before I can run the rsync
> command.
>
> I've looked at threading, but that seems excessive. There must be an
> easier way. Whatever I do, though, I'll need to use pexpect to spawn the
> processes, since I'll need to log in to ssh servers with a password.
>
> Thanks for any help.
>
> --Jesse
>
>
I am not sure I understand you correctly (my english is a bit limited)
Can you not use something like:
rsync --timeout=5 -e "ssh --with-many-options"
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Re: Straight line detection
PyPK wrote: > Does anyone know of a simple implementation of a straight line > detection algorithm something like hough or anything simpler.So > something like if we have a 2D arary of pixel elements representing a > particular Image. How can we identify lines in this Image. > for example: > > ary = > [[1,1,1,1,1], > [1,1,0,0,0], > [1,0,1,0,0], > [1,0,0,1,0], > [1,0,0,0,1]] > So if 'ary' represents pxl of an image which has a horizontal line(row > 0),a vertical line(col 0) and a diagonal line(diagonal of ary). then > basically I want identify any horizontal or vertical or diagonal line > anywhere in the pxl array. > > Thanks. > I would recommend using a module for computing, my choice would be numarray: www.stsci.edu/resources/software_hardware/numarray You could even write your own version of hough, should not be too complex. A fwee things you need to consider: 1) Are all the lines through the image, or would a row with [0,0,1 ...(a few dozen ones in here) ... 1,0] be a line? 2) Do you also need edge detection? Then you might need to convolve the image with a Laplacian or something like that, e.g. new[i,j] = (4*old[i,j])-old[i-1,j]-old[i+1,j]-old[i,j-1]-old[i,j+1] 3) How "full" are the images? It is much easier if only a small fraction of your image is lines, in your example more than half of image pixels are lines. 4) How big images are you processing? I always have at least one million pixels, so the rest may not work for small images. To do some quicklook checks you can of course go through each row/column and check if the values are different enough, something like mat = numarray.array(ima) x = mat.mean() dx = mat.stddev() then check if some rows are different from others, maybe (mat[:,i].mean() > (x + N*dx)) for "white" lines or (mat[:,i].mean() < (x - N*dx))) for "black" lines you probably need do a few tests to get a good value of N. repeat for columns (mat[j,:]) and diagonals: numarray.diagonal(mat,o) where o is offset from mat[0,0] and if you need non-diagonal elements, say ima = [[1 0 0 0 0] [0 0 1 0 0] [0 0 0 0 1]] would contain a line of ones, then vect = ima.flat gives the image as a rank-1 array and you can then take strides (every nth element) just like with normal lists, array[a:b:n] takes every nth element in array[a:b], so vect[::7] would be [1 1 1] I hope this helps a bit. -- http://mail.python.org/mailman/listinfo/python-list
Re: Changing the module not taking effect in calling module
Gopal wrote: > Hi, > > I've a module report.py having a set of funtions to open/close/write > data to a log file. I invoke these functions from another module > script.py. > > Whenever I'm changing something in report.py, I'm running the file > (however, it has not effect). After that I'm running script.py again. > However, the output is not taking effect. > > If I shut the IDLE interpreter and all the other files and then reopen > again; and then run script.py, the output is taking effect. > > Is there any way to improve it? I'm new to Python. > > -Gopal. > you could try "reload(module)" instead of "import module" or running the file. -- http://mail.python.org/mailman/listinfo/python-list
Re: plateform info.
Monu Agrawal wrote: > Hi I want to know whether the program is being run on windows or on > Xnix. Is there any variable or method which tells me that it's windows? > os.name - the value is "posix" for Linux/Unix, "nt" or "ce" for Windows, and so on... -- http://mail.python.org/mailman/listinfo/python-list
