Re: [Tutor] How can I copy files recursively?
directory structure. Something like:
source = '/ipodder'
dest = '/foo/bar'
for root, dirs, files in os.walk(source):
for f in files:
os.rename(os.path.join(root, f), os.path.join(dest, f))
A helper function here will be useful. We can simulate something like:
find . -name '*.mp3'
with:
#
import os, fnmatch
def find_with_glob(dir, pattern):
find_with_glob: string string - listof(string)
Returns a list of all the files that can be found
in dir or subdirectories, matching the globbing pattern.
For example: find_with_glob('.', '*.mp3').
results = []
for root, dirs, files in os.walk(dir):
for f in files:
if fnmatch.fnmatch(f, pattern):
results.append(os.path.join(root, f))
return results
#
The reason this ends up a bit verbose compared to the shell is because the
shell's 'find' utility is doing a lot of work too. But if we were to do a
simple lookup for mp3 files, I agree that using Unix's 'find' would be the
simplest approach.
One advantage we have in using Python here is generality: we can, with a
little work, plug in a different kind of filter here: rather than use
globs, we can use full-fledged regular expressions.
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Re: [Tutor] How can I copy files recursively?
John Fouhy wrote:
On 11/07/06, Richard Querin [EMAIL PROTECTED] wrote:
I know this is probably a dumb question:
I've got mp3 files that are downloaded (by ipodder) into individual
subfolders. I'd like to write a quick script to move (not copy) all the mp3
files in those folders into a single destination folder. I was thinking I
could do it easily from the linux command line (cp -r copies the subfolders
out as well) but I can't figure out how to do it. Is there an easy way to
achieve this using Python? I am assuming this would be something Python was
designed to make easy..
In python, you can use os.rename to move and os.walk to walk your
directory structure. Something like:
source = '/ipodder'
dest = '/foo/bar'
for root, dirs, files in os.walk(source):
for f in files:
os.rename(os.path.join(root, f), os.path.join(dest, f))
This will copy all the files into the dest directory - it doesn't copy
the folder structure.
I highly recommend Jason Orendorff's path module for any code involving
walking directories. Something like this:
from path import path
source = path('/ipodder')
dest = '/foo/bar'
for mp3 in source.walkfiles('*.mp3'):
relpath = source.relpathto(mp3)
destmp3 = dest / relpath
os.rename(mp3, destmp3)
http://www.jorendorff.com/articles/python/path/index.html
Kent
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[Tutor] Need Help
Title: [Tutor] Need Help Here is the assignment You've been given an assignment by your supervisor to program a small application to monitor the current status of the cash account in the firm's petty cash fund (the amount of cash kept on hand in the office for incidental purchases). The requirements for the program are to allow users to input the amount of cash deposited, the amount of cash withdrawn and to get a report of the balance at any given time. You will need to also add the date of each deposit and the date of each withdrawal and provide a date with the balance returned upon a given query. The program should be able to provide a printed report and support a command line query. You are to use the object oriented properties of Python to accomplish this task. This is where I am at so far. I don't understand how to get the Account class into the program. Can you help a little, Just looking for an idea or some guidance #!/usr/bin/python # Filename: petty cash.py print Welcome to the petty cash account print Did you deposit or withdrawl money today print # print out menu print please select a number print 1 for deposit print 2 for withdrawl # Get user's choice: number = input () # if number == 1: deposit = input (how much?) print I deposited:, deposit elif number == 2: withdrawl = input (How Much?) print I withdrew:, withdrawl print what is today's date? # Get date from user date = input () This is where I get stuck. The program will allow me to input the deposit or withdrawl ammount and the date but does nothing ownce it gets here class Account: def __init__(self, initial): self.balance = initial def deposit(self, amt): self.balance = self.balance + amt def withdraw(self,amt): self.balance = self.balance - amt def getbalance(self): return self.balance V/R CW2 John Shappell HHB 2-44 ADA BN Work 270-798-6823 FAX 775-618-2455 [EMAIL PROTECTED] [EMAIL PROTECTED] ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
Hi. Shappell, John J CW2 wrote: Here is the assignment [snip assignment] Please don't ask about homework in the future. Did your professor tell you to submit queries to this list? If so, could you ask him not to? it's against the policies of the tutor mailing list to give homework help. However, I can give you a few hints about python in general. The rules may be different but my impression was that there was no homework to be submitted here. If I'm wrong please correct me. This is where I am at so far. I don't understand how to get the Account class into the program. Can you help a little, Just looking for an idea or some guidance #!/usr/bin/python # Filename: petty cash.py print Welcome to the petty cash account print Did you deposit or withdrawl money today print # print out menu print please select a number print 1 for deposit print 2 for withdrawl # Get user's choice: number = input () I suggest doing something like number = int(raw_input( )) I'm pretty sure the 'input' statement is a no-no, unless your Professor says, and then you should use it. # if number == 1: deposit = input (how much?) print I deposited:, deposit elif number == 2: withdrawl = input (How Much?) print I withdrew:, withdrawl print what is today's date? # Get date from user date = input () *This is where I get stuck. The program will allow me to input the deposit or withdrawl ammount and the date but does nothing ownce it gets here* class Account: def __init__(self, initial): self.balance = initial def deposit(self, amt): self.balance = self.balance + amt def withdraw(self,amt): self.balance = self.balance - amt def getbalance(self): return self.balance What you have there is a class, not an instance of a class. read more about the difference at http://www.python.org/doc/2.2.3/tut/node11.html or some other tutorial site. Also, make it clear to your instructor that you had trouble here. If he doesn't know what's hanging people up he won't be able to help you with it. [EMAIL PROTECTED] [EMAIL PROTECTED] What was your job in the Army, if you don't mind my asking? Cheers. -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] printing 00
+++ Christopher Spears [10-07-06 21:34 -0700]: | I'm working on a problem from How To Think Like A | Computer Scientist. I created a Time class: | | class Time: | | def __init__(self, hours, minutes, seconds): | self.hours = hours | self.minutes = minutes | self.seconds = seconds | | I created a function to print the Time object: | | def printTime(time): | print %d:%d:%d % (time.hours, time.minutes, | time.seconds) | | However, when I type '00', I get the following: | time = Time(12,34.4,00) | printTime(time) | 12:34:0 | time.seconds | 0 instead of %d you may use %02d. Shantanoo -- It's not what you look at that matters, it's what you see. ~Henry David Thoreau ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How can I copy files recursively?
On 7/10/06, Richard Querin [EMAIL PROTECTED] wrote: I know this is probably a dumb question:I've got mp3 files that are downloaded (by ipodder) into individual subfolders. I'd like to write a quick script to move (not copy) all the mp3 files in those folders into a single destination folder. I was thinking I could do it easily from the linux command line (cp -r copies the subfolders out as well) but I can't figure out how to do it. Is there an easy way to achieve this using Python? I am assuming this would be something Python was designed to make easy.. Python makes things easy, from a certain point of view. You have to think that Python is a program language and not a command language (like Bourne shell).Others have a number of solutions that will move your files with os.walk and os.path.walk. They are nice, but sometimes it's better to traverse the tree individually. Also, you didn't specify if the destination folder structure already existed, or if it will need to be created (which cp -r will do). The following should handle that case for you: import fnmatch, osdef movetree(srcdir, dstdir, pattern=None): # dstdir must exist first srcnames = os.listdir(srcdir) for name in srcnames: srcfname = os.path.join(srcdir, name) dstfname = os.path.join(dstdir, name) if os.path.isdir(srcfname): os.mkdir(dstfname, 00) movetree(srcfname, dstfname) elif pattern is None or fnmatch.fnmatch(name, pattern): os.rename(srcfname, dstfname) You could do the same with os.walk or os.path.walk, but the recursive nature of the function takes care of itself a bit better, IMO. -Arcege-- There's so many different worlds,So many different suns.And we have just one world, But we live in different ones. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] tempfile and passing files around
I have an issue with the tempfile module that I can't figure out.
Snippet of relevant script looks like so:
1 bob = tempfile.NamedTemporaryFile()
2 bob.write('Hallo!')
3 bob.read()
4 sam = tempfile.NamedTemporaryFile()
5 bobHandle = file(bob.name)
6 bobHandle.read()
As you can see, I'm creating two NamedTemporaryFiles and then reading
from the first. Line 3 doesn't really do anything, there's no output
because we're reading at the end of the file, but as long as I leave
it in, line 6 will output the expected 'Hallo!'. If I remove it,
there's no output from line 6.
I really stumbled upon this, and it looks like, if you create a
tempfile and write to it, then create another tempfile, you can only
open up the first to read it again if you do a read method on the
first file before you open it. I dunno, just kinda baffled.
TIA, gabe
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Re: [Tutor] tempfile and passing files around
Gabriel Farrell wrote:
I have an issue with the tempfile module that I can't figure out.
Snippet of relevant script looks like so:
1 bob = tempfile.NamedTemporaryFile()
2 bob.write('Hallo!')
3 bob.read()
4 sam = tempfile.NamedTemporaryFile()
5 bobHandle = file(bob.name)
6 bobHandle.read()
As you can see, I'm creating two NamedTemporaryFiles and then reading
from the first. Line 3 doesn't really do anything, there's no output
because we're reading at the end of the file, but as long as I leave
it in, line 6 will output the expected 'Hallo!'. If I remove it,
there's no output from line 6.
Try bob.flush() instead of bob.read(), my guess is the read() is forcing
a flush().
Kent
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Re: [Tutor] Need Help
On Tue, 11 Jul 2006 06:41:23 -0500 Luke Paireepinart [EMAIL PROTECTED] wrote: Hi. Shappell, John J CW2 wrote: Here is the assignment [snip assignment] Please don't ask about homework in the future. Did your professor tell you to submit queries to this list? If so, could you ask him not to? it's against the policies of the tutor mailing list to give homework help. However, I can give you a few hints about python in general. The rules may be different but my impression was that there was no homework to be submitted here. If I'm wrong please correct me. Perhaps I am wrong, Luke but my impression was that this request was fine. He openly stated it was homework and he did considerable work on it before getting stuck. Also he specifically did not ask for a solution but wished to be nudged in the right direction. I am sorry that I do not have the knowledge to help but perhaps your tip did the trick. Perhaps Danny or Kent would clarify this situation. John Montgomery ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] tempfile and passing files around
On Tue, Jul 11, 2006 at 03:04:02PM -0400, Kent Johnson wrote: Try bob.flush() instead of bob.read(), my guess is the read() is forcing a flush(). That works! Thanks, Kent. If I understand flush (looking at [1]), I got no output because the data for the stream wasn't written to the file before I tried to read it. Is that right? [1] http://www.opengroup.org/pubs/online/7908799/xsh/fflush.html ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] tempfile and passing files around
Gabriel Farrell wrote: On Tue, Jul 11, 2006 at 03:04:02PM -0400, Kent Johnson wrote: Try bob.flush() instead of bob.read(), my guess is the read() is forcing a flush(). That works! Thanks, Kent. If I understand flush (looking at [1]), I got no output because the data for the stream wasn't written to the file before I tried to read it. Is that right? Yes, that's right. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
John or Margaret Montgomery wrote: On Tue, 11 Jul 2006 06:41:23 -0500 Luke Paireepinart [EMAIL PROTECTED] wrote: Hi. Shappell, John J CW2 wrote: Here is the assignment [snip assignment] Please don't ask about homework in the future. Did your professor tell you to submit queries to this list? If so, could you ask him not to? it's against the policies of the tutor mailing list to give homework help. However, I can give you a few hints about python in general. The rules may be different but my impression was that there was no homework to be submitted here. If I'm wrong please correct me. Perhaps I am wrong, Luke but my impression was that this request was fine. He openly stated it was homework and he did considerable work on it before getting stuck. Also he specifically did not ask for a solution but wished to be nudged in the right direction. I am sorry that I do not have the knowledge to help but perhaps your tip did the trick. Perhaps Danny or Kent would clarify this situation. By posting the entire homework problem, John Shappell did give the impression that he wanted us to do the problem for him, but as John Montgomery notes he is just looking for a hint in an area where he is stuck. That is fine for the tutor list. Since we know it is homework we can use a light touch and avoid giving the entire solution. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] Help IDLE Compile Problem
Hi,I have two Python source files within editing them via IDLE.I have a problem. The second file is used by the first file. Some partsi mean from the second file is used. But when i change the contents of the second file and while i'm running the first file with F5, change doesnt reflectto the runtime. If i close two IDLE windows and delete .pyc of the second filethen it is ok. What is the problem ? ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How can I copy files recursively?
subfolders. I'd like to write a quick script to move (not copy) all the mp3 files in those folders into a single destination folder. I was thinking I could do it easily from the linux command line (cp -r copies the subfolders out as well) but I can't figure out how to do it. Is there an easy way to achieve this using Python? I am assuming this would be something Python was designed to make easy.. Things which are easy in the shell are usually less easy in Python. In your case a simple cp -r will copy the files and an rm -rf will delete the originals. Or you could just use mv on the top level folder. However the OS topic in my tutor provides all the bits you need to write a python script if you really need to. Alan G. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How can I copy files recursively?
On 7/11/06, Alan Gauld [EMAIL PROTECTED] wrote: Things which are easy in the shell are usually less easy in Python.In your case a simple cp -r will copy the files and an rm -rf willdelete the originals.Or you could just use mv on the top level folder. But I don't want the sub folders to come along with the copy. I'd like to grab the mp3 files out of a set of subfolders and place them all into a single folder somewhere else. I'm completely lost when it comes to bash scripting, so I may take Michael P. Reilly's suggestion as a starting point since it's the only one I understand at first glance ;). I'm really a newbie to python programming so readability and understanding it is first on my list. Efficiency and speed is secondary to me at the moment.Thanks to all for the help. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Help IDLE Compile Problem
Bugra Cakir wrote: Hi, I have two Python source files within editing them via IDLE. I have a problem. The second file is used by the first file. Some parts i mean from the second file is used. But when i change the contents of the second file and while i'm running the first file with F5, change doesnt reflect to the runtime. If i close two IDLE windows and delete .pyc of the second file then it is ok. What is the problem ? Your question is hard to address because we don't know what you mean by The second file is used by the first file. I will assume you are importing it. Import runs the imported module once. Subsequent executions of import do NOT rerun the module. Therefore any changes you make to it are not showing up. To work around this problem, after importing, use the reload function: import foo reload(foo) -- Bob Gailer 510-978-4454 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
[snip assignment] Please don't ask about homework in the future. Did your professor tell you to submit queries to this list? If so, could you ask him not to? it's against the policies of the tutor mailing list to give homework help. Thats a bit extreme. We don't mind giving help on specific queries where an attempt has been made to do the work. We will rarely give a direct answer but might ask questions or make suggestions to lead you towards the answer. What we will not do is accept a simple query saying, in effect, here is the assignment, how do I do it? This is where I am at so far. I don't understand how to get the Account class into the program. Can you help a little, Just looking for an idea or some guidance Do you understand the difference between classes and objects? Do you understand how to create an object, as opposed to a class? Do you know how to call the methods of an object once created? If not find almost any Python tutorial. They all answer those questions. class Account: def __init__(self, initial): self.balance = initial def deposit(self, amt): self.balance = self.balance + amt def withdraw(self,amt): self.balance = self.balance - amt def getbalance(self): return self.balance What you have there is a class, not an instance of a class. read more about the difference at http://www.python.org/doc/2.2.3/tut/node11.html or some other tutorial site. Seconded. Also, make it clear to your instructor that you had trouble here. If he doesn't know what's hanging people up he won't be able to help you with it. But I think Luke is being a wee bit hard here, you clearly have tried to solve it, you just need some direction. I'd say that was within the tutor list rules. Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
By posting the entire homework problem, John Shappell did give the impression that he wanted us to do the problem for him, but as John Montgomery notes he is just looking for a hint in an area where he is stuck. That is fine for the tutor list. Since we know it is homework we can use a light touch and avoid giving the entire solution. The idea is to try attacking the core of the problem the questioner has. In that sense, I try not to look at the details of the homework problem. As a concrete example, if someone comes up and says: I don't know how to get my name-asking program to stop when the user enters quit. Help! I'll translate this to: 1. I might not know how to use boolean conditionals. 2. I might not know how to use loops. 3. I might not know how to use these two things together. 4. I don't understand the question I'm being asked, or why this is useful. That is, I'd ignore the surface details about asking about string comparison, but concentrate on figuring out which of these things the questioner is confused with. Or there may be something that hasn't been accounted for... The questions we ask from then on are meant to probe. It would be very cruel to not address the core reason why the student's struggling. That's why we don't answer homework questions: it doesn't address what's often a much bigger problem with the student's concepts of programming. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] How can I copy files recursively?
Or you could just use mv on the top level folder. But I don't want the sub folders to come along with the copy. I'd like to grab the mp3 files out of a set of subfolders and place them all into a single folder somewhere else. Ah, sorry, I misunderstood the question. In that case os.walk and shutil.copy provide a fairly easy solution. Take a look at the findfile() function in the OS tutor topic. Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] modbus communication with python?
okay, yes thank you! I have seen this, although I looked a the code and it appears that this is actually a modbus server (please correct me if I am wrong, I am really new to modbus and PLC's). We are already using a modbus server (KEPDirect for PLC's, automation direct) and I beleive we are using a Koyo PLC. but I simply want to read and write values stored on the modbus server, I don't actually want to create a new server. I'm not sure that this module is the way to go (although again I might be wrong), what might be my other options and where should I go to learn about this? thanks!JeffJason Massey [EMAIL PROTECTED] wrote: Googling for modbus python turned up:https://lintouch.org/repos/lintouch/lsp-modbus/trunk/tests/ On 7/5/06, Jeff Peery [EMAIL PROTECTED] wrote: Hello, I need to talk read write to a modbus so that I can work with a PLC. I have not a clue how this all works. does python have a modbus module or where might I look to find how to do this? thanks. JeffHow low will we go? Check out Yahoo! Messenger's low PC-to-Phone call rates. ___Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor Talk is cheap. Use Yahoo! Messenger to make PC-to-Phone calls. Great rates starting at 1/min.___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
On 7/10/06, Shappell, John J CW2 [EMAIL PROTECTED] wrote: Here is the assignment You've been given an assignment by your supervisor to program a small application to monitor the current status of the cash account in the firm's petty cash fund (the amount of cash kept on hand in the office for incidental purchases). The requirements for the program are to allow users to input the amount of cash deposited, the amount of cash withdrawn and to get a report of the balance at any given time. You will need to also add the date of each deposit and the date of each withdrawal and provide a date with the balance returned upon a given query. The program should be able to provide a printed report and support a command line query. You are to use the object oriented properties of Python to accomplish this task. This is where I am at so far. I don't understand how to get the Account class into the program. Can you help a little, Just looking for an idea or some guidance #!/usr/bin/python # Filename: petty cash.py print Welcome to the petty cash account print Did you deposit or withdrawl money today print # print out menu print please select a number print 1 for deposit print 2 for withdrawl # Get user's choice: number = input () # if number == 1: deposit = input (how much?) print I deposited:, deposit elif number == 2: withdrawl = input (How Much?) print I withdrew:, withdrawl print what is today's date? # Get date from user date = input () This is where I get stuck. The program will allow me to input the deposit or withdrawl ammount and the date but does nothing ownce it gets here class Account: def __init__(self, initial): self.balance = initial def deposit(self, amt): self.balance = self.balance + amt def withdraw(self,amt): self.balance = self.balance - amt def getbalance(self): return self.balance John, Another aspect of your assignment will be to be able to use this functionality from the command-line. This means: without asking questions from the user, but input is being passed as arguments. You will eventually have to think how this will affect the structure of your program. -Arcege-- There's so many different worlds,So many different suns.And we have just one world,But we live in different ones. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
Shappell, John J CW2 wrote: Here is the assignment 1. You've been given an assignment by your supervisor to program a small application to monitor the current status of the cash account in the firm's petty cash fund (the amount of cash kept on hand in the office for incidental purchases). The requirements for the program are to allow users to input the amount of cash deposited, the amount of cash withdrawn and to get a report of the balance at any given time. You will need to also add the date of each deposit and the date of each withdrawal and provide a date with the balance returned upon a given query. The program should be able to provide a printed report and support a command line query. You are to use the object oriented properties of Python to accomplish this task. This is where I am at so far. I don't understand how to get the Account class into the program. Can you help a little, Just looking for an idea or some guidance #!/usr/bin/python # Filename: petty cash.py print Welcome to the petty cash account print Did you deposit or withdrawl money today print # print out menu print please select a number print 1 for deposit print 2 for withdrawl # Get user's choice: number = input () # if number == 1: deposit = input (how much?) print I deposited:, deposit elif number == 2: withdrawl = input (How Much?) print I withdrew:, withdrawl print what is today's date? # Get date from user date = input () *This is where I get stuck. The program will allow me to input the deposit or withdrawl ammount and the date but does nothing ownce it gets here* class Account: def __init__(self, initial): self.balance = initial def deposit(self, amt): self.balance = self.balance + amt def withdraw(self,amt): self.balance = self.balance - amt def getbalance(self): return self.balance Hi John, You need to create an instance of Account and post the transactions to it by calling instance methods on the account. The Account class may need to keep track of the individual postings as well as the total balance. There is a lot to the assignment - is this one of your first assignments or a later one? Without a bit of context of where you are in the course it's hard to know what is expected. It sounds like you may need some kind of persistent storage like a database but I don't know if you have learned anything about that yet. Kent ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] no loops
I am working on another problem from How To Think Like A Computer Scientist. Here is a function: def increment(time, seconds): time.seconds = time.seconds + seconds while time.seconds = 60: time.seconds = time.seconds - 60 time.minutes = time.minutes + 1 while time.minutes = 60: time.minutes = time.minutes - 60 time.hours = time.hours + 1 Here is the function in action: from time import * atime = Time() atime.hours = 1 atime.minutes = 60 atime.seconds = 120 printTime(atime) 1:60:120 increment(atime,1) printTime(atime) 2:2:1 Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. -Chris ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] no loops
Christopher Spears schrieb: IF you know that it's 2 seconds after midnight, how many hours, minutes, seconds after midnight ist this. If you should compute this by hand, how would you proceed? Best wishes, Gregor I am working on another problem from How To Think Like A Computer Scientist. Here is a function: def increment(time, seconds): time.seconds = time.seconds + seconds while time.seconds = 60: time.seconds = time.seconds - 60 time.minutes = time.minutes + 1 while time.minutes = 60: time.minutes = time.minutes - 60 time.hours = time.hours + 1 Here is the function in action: from time import * atime = Time() atime.hours = 1 atime.minutes = 60 atime.seconds = 120 printTime(atime) 1:60:120 increment(atime,1) printTime(atime) 2:2:1 Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. -Chris ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] no loops
On 12/07/06, Christopher Spears [EMAIL PROTECTED] wrote: Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. Hi Chris, You are using iteration. That's what loops are :-) Perhaps you meant to say recursion, which is where a function calls itself. You could solve this recursively, but I think Gregor's comment is closer to what they want you to do. -- John. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
On Tue, 11 Jul 2006, Michael P. Reilly wrote: Another aspect of your assignment will be to be able to use this functionality from the command-line. This means: without asking questions from the user, but input is being passed as arguments. John should get clarification from his instructor, but I did not read it that way. I read that requirement to support a command line query as meaning the program should prompt the user to enter a query command; as opposed to hard-coding the transactions in the coe itself (as is sometimes done at an intro level). ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] quickie: a better dynamic dictionary update?
Hi,I need to keep an updated dictionary of pictures in my application. I have a function which takes snapshots of the current pictures available. Some of the pictures in my dictionary have been deleted, so their dict entry needs to be removed. Here is a snippet of very ugly code I have which works. I'm looking for quick suggestions for a better implementation-- all nice replies welcomed! Thanks,Marcus-- code snippet# 1st, find the 'stale' items in our dictionary to delete# lstKeepers is a list of current pictures# Note: if I try to iterate over the keys of the dict and # remove-as-I-go, I get an exception (dict size changed# during iteration)lstRemove = []for key in myDict: if key not in lstKeepers: lstRemove.append(key)# 2nd, remove themfor oldKey in lstRemove: del myDict[oldKey] ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] no loops
--- John Fouhy [EMAIL PROTECTED] wrote: On 12/07/06, Christopher Spears [EMAIL PROTECTED] wrote: Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. Hi Chris, You are using iteration. That's what loops are :-) Perhaps you meant to say recursion, which is where a function calls itself. You could solve this recursively, but I think Gregor's comment is closer to what they want you to do. -- John. I agree with Gregor and John. What makes the problem difficult is the fact that time is represented using 3 different units of measure: hours, minutes, and seconds. The math becomes much simpler if you convert the time value to a single unit (such as seconds). But it doesn't have to be seconds. I recall seeing one database that stores time as fractional hours where a minute is worth 1/60 of an hour and a second is worth 1/3600 of an hour. In other words, 1:15 is stored as 1.25 hours, 4:30 is stored as 4.5 hours, and so forth. Converting from (hours, minutes, seconds) to fractional hours is pretty easy, but going the other way is not so simple. __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Need Help
--- Terry Carroll [EMAIL PROTECTED] wrote: On Tue, 11 Jul 2006, Michael P. Reilly wrote: Another aspect of your assignment will be to be able to use this functionality from the command-line. This means: without asking questions from the user, but input is being passed as arguments. John should get clarification from his instructor, but I did not read it that way. I read that requirement to support a command line query as meaning the program should prompt the user to enter a query command; as opposed to hard-coding the transactions in the coe itself (as is sometimes done at an intro level). ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor This may be the most important lesson to learn from this exercise: even experienced programmers can (and do) interpret requirements differently. When in doubt, ask! __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] quickie: a better dynamic dictionary update?
On Tue, 11 Jul 2006, Marcus Goldfish wrote: # 1st, find the 'stale' items in our dictionary to delete # lstKeepers is a list of current pictures # Note: if I try to iterate over the keys of the dict and # remove-as-I-go, I get an exception (dict size changed # during iteration) lstRemove = [] for key in myDict: if key not in lstKeepers: lstRemove.append(key) # 2nd, remove them for oldKey in lstRemove: del myDict[oldKey] lstDeleters = [key for key in myDict.keys() if key not in lstKeepers] for key in lstDeleters: del myDict[key] It's still a two-passer, but I don't see straightforward any way around that, if you want to update the dictionary (as opposed to making a new dictionary with the result, which could probably be done with an excessively clever list comprehension). ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] quickie: a better dynamic dictionary update?
On Tue, 11 Jul 2006, Terry Carroll wrote: On Tue, 11 Jul 2006, Marcus Goldfish wrote: # 1st, find the 'stale' items in our dictionary to delete # lstKeepers is a list of current pictures # Note: if I try to iterate over the keys of the dict and # remove-as-I-go, I get an exception (dict size changed # during iteration) lstRemove = [] for key in myDict: if key not in lstKeepers: lstRemove.append(key) # 2nd, remove them for oldKey in lstRemove: del myDict[oldKey] [snip code] It's still a two-passer, but I don't see straightforward any way around that, if you want to update the dictionary (as opposed to making a new dictionary with the result, which could probably be done with an excessively clever list comprehension). Actually, it turns out not to be excessively clever at all (if I could do it): myDict = dict([(key, myDict[key]) for key in myDict.keys() if key in lstKeepers]) I'm not sure it's any nicer looking, though, than my first suggestion (although my first suggestion is probably a little slower). ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] no loops
Christopher Spears wrote: I am working on another problem from How To Think Like A Computer Scientist. Here is a function: def increment(time, seconds): time.seconds = time.seconds + seconds while time.seconds = 60: time.seconds = time.seconds - 60 time.minutes = time.minutes + 1 while time.minutes = 60: time.minutes = time.minutes - 60 time.hours = time.hours + 1 Here is the function in action: from time import * atime = Time() atime.hours = 1 atime.minutes = 60 atime.seconds = 120 printTime(atime) 1:60:120 increment(atime,1) printTime(atime) 2:2:1 Now the exercise is: As an exercise, rewrite this function so that it doesn't contain any loops. I have been staring at this function and drawing a blank. Something tells me that I need to use iteration, but I am not sure how I could implement it. take a look at the divmod built-in function. -- Bob Gailer 510-978-4454 ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] quickie: a better dynamic dictionary update?
On 12/07/06, Marcus Goldfish [EMAIL PROTECTED] wrote: # 1st, find the 'stale' items in our dictionary to delete # lstKeepers is a list of current pictures # Note: if I try to iterate over the keys of the dict and # remove-as-I-go, I get an exception (dict size changed # during iteration) Try this: for key in myDict.keys(): if key not in lstKeepers: del myDict[key] The difference here is that myDict.keys() creates a list containing the keys of myDict at the start of the loop, and then iterates over the list. If lstKeepers is big, it might be more efficient to make it into a set first --- keepSet = set(lstKeepers) for key in myDict.keys(): if key not in keepSet: del myDict[key] -- John. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
[Tutor] How do I get my machine to run an SMTP server?
This is a program that I wrote using the
third example at 12.2.13 Examples at python.org.
#!/usr/bin/env python
"""Send the contents of a directory as a MIME
message.
Usage: dirmail [options] from to [to
...]*
Options: -h /
--help Print this message and
exit.
-d
directory
--directory=directory Mail the
contents of the specified directory, otherwise use
the current directory. Only
the regular files in the directory are
sent, and we don't recurse to
subdirectories.
`from' is the email address of the sender of the
message.
`to' is the email address of the recipient of the
message, and multiplerecipients may be given.
The email is sent by forwarding to your local SMTP
server, which then does thenormal delivery process. Your local machine
must be running an SMTP server."""
import sysimport osimport getoptimport
smtplib# For guessing MIME type based on file name extensionimport
mimetypes
from email import Encodersfrom email.Message
import Messagefrom email.MIMEAudio import MIMEAudiofrom email.MIMEBase
import MIMEBasefrom email.MIMEMultipart import MIMEMultipartfrom
email.MIMEImage import MIMEImagefrom email.MIMEText import
MIMEText
COMMASPACE = ', '
def usage(code, msg=''): print
sys.stderr, __doc__ if
msg: print sys.stderr,
msg sys.exit(code)
def main():
try: opts, args =
getopt.getopt(sys.argv[1:], 'C:', ['help', 'directory='])
except getopt.error, msg: usage(1,
msg)
dir = os.curdir for opt, arg in
opts: if opt in ('-h',
'--help'):
usage(0) elif opt in ('-d',
'--directory'):
dir = arg
if len(args)
2: usage(1)
sender = args[0] recips =
args[1:]
# Create the enclosing (outer)
message outer = MIMEMultipart()
outer['Subject'] = 'Contents of directory %s' % os.path.abspath('C:\Documents
and Settings\User\\My Documents') outer['To'] =
COMMASPACE.join('[EMAIL PROTECTED]')
outer['From'] = '[EMAIL PROTECTED]'
outer.preamble = 'You will not see this in a MIME-aware mail
reader.\n' # To guarantee the message ends with a
newline outer.epilogue = ''
for filename in os.listdir('C:\Documents and
Settings\User'): path =
os.path.join('C:\Documents and Settings\User', 'My
Documents') if not
os.path.isfile('C:\Documents and
Settings\User'):
continue # Guess the content type
based on the file's extension.
Encoding # will be ignored,
although we should check for simple things
like # gzip'd or compressed
files. ctype, encoding =
mimetypes.guess_type('C:\Documents and Settings\User\\My
Documents') if ctype is None or
encoding is not
None: # No
guess could be made, or the file is encoded (compressed),
so # use a
generic bag-of-bits
type.
ctype = 'application/octet-stream'
maintype, subtype = ctype.split('/',
1) if maintype ==
'text': fp
= open('C:\Documents and Settings\User\\My
Documents')
# Note: we should handle calculating the
charset
msg = MIMEText(fp.read(),
_subtype=subtype)
fp.close() elif maintype ==
'image':
fp = open('C:\Documents and Settings\User\\My Documents',
'rb') msg
= MIMEImage(fp.read(),
_subtype=subtype)
fp.close() elif maintype ==
'audio':
fp = open('C:\Documents and Settings\User\\My Documents',
'rb') msg
= MIMEAudio(fp.read(),
_subtype=subtype)
fp.close()
else: fp =
open('C:\Documents and Settings\User\\My Documents',
'rb') msg
= MIMEBase(maintype,
subtype)
msg.set_payload(fp.read())
fp.close()
# Encode the payload using
Base64
Encoders.encode_base64(msg) # Set
the filename parameter
msg.add_header('Content-Disposition', 'attachment',
filename=filename)
outer.attach(msg)
# Now send the message s =
smtplib.SMTP() s.connect()
__init__(self, host='', port=25, local_hostname=None)
s.sendmail('[EMAIL PROTECTED]', '[EMAIL PROTECTED]',
outer.as_string()) s.close()
if __name__ == '__main__': main()
When I run the program using IDLE, I get the
following:
Send the contents of a directory as a MIME message.
Usage: dirmail [options] from to [to ...]*
Options: -h /
--help Print this message and
exit.
-d directory
--directory=directory Mail the
contents of the specified directory, otherwise use
the current directory. Only
the regular files in the directory are
sent, and we don't recurse to
subdirectories.
`from' is the email address of the sender of the message.
`to' is the email address of the recipient of the message, and
multiplerecipients may be given.
The email is sent by forwarding to your local SMTP server, which then does
thenormal delivery process. Your local machine must be running an SMTP
server.
Traceback (most recent call last): File "C:\Documents and
Settings\User\Desktop\EB2.py", line 125, in ?
main() File "C:\Documents and Settings\User\Desktop\EB2.py", line 65,
in main usage(1) File "C:\Documents and
Settings\User\Desktop\EB2.py", line 48, in usage
sys.exit(code)SystemExit: 1
I guess that my first question is how do I get my machine to run an
SMTP server?
Also, I'd like to say that I greatly appreciate all of the help
that I've gotten in the
Re: [Tutor] Need Help
[snip] It would be very cruel to not address the core reason why the student's struggling. That's why we don't answer homework questions: it doesn't address what's often a much bigger problem with the student's concepts of programming. Thank you for this explanation, Danny. I thought there was a zero-tolerance policy on homework, not that we were supposed to give them more general help than a specific answer. I agree my original choice of words was harsh. It didn't sound that way to me when I wrote it, and I apologize to the OP. It's also better that they tell us it's a homework problem than trying to mislead us, I reckon. Anyway, does the Original Poster have any more questions or have we answered them all? -Luke ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
