🌐 Mailman 3 December 2002 - Tutor - python.org

Backslashes inside of variable
by Phoebus Nov. 24, 2003

Nov. 24, 2003

I am running Python 2.2 on Win2k. I have a program which writes a filename, with backslashes to a file, along with other stuff. I read the file in using readlines() and put each line into a variable. My problem is I want to use the filename, but I can't use it because of the backslashes. I know about doing open(r"d:\test\file.txt","w") or even open(`d:\test\file.txt`,"w"), but the filename is inside of a variable so when I do open(filename,'w'), I have problems. Can anyone help? Thanks, Steve --

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[Baypiggies] ANN: BayPIGgies mtg Wed 11/13 7:30pm (fwd)
by Wesley Chun April 4, 2003

April 4, 2003

BayPIGgies: Silicon Valley-San Francisco Bay Area Python Users Group When: December 11, 2002 @ 7:30pm Where: Stanford University, Palo Alto, CA Agenda: Newbies' Nite Speaker: (everyone!) Due to popular demand, we are having another Newbie Night (e.g. April 2002). This is the chance for all Python programmers to bring their friends and colleagues who should hear about Python. It is also for those who want to or are picking up Python and have questions! We will have a good number of Python experts who will try and help you out. Perl and Java experts are welcome too, as many Python developers also have experience there and can give you an honest comparison. The format is this: Wesley (or Danny) will give just a short half-hour intro presentation on Python to beginners followed by a quick demo, and then we will open it up to everyone for Q&A. Mingling and networking will bring our meeting to a glorious conclusion. :-) # NOTE: the next meeting on January 8, 2003 will be not be at the usual # place... stay tuned for a location update. # Call For Talks: We are actively seeking speakers for BayPIGgies! If you would like to give a talk at one of our 2003 meetings (any Python related topic), contact us to coordinate! more info including directions: http://www.baypiggies.net hope to see some of you next Wednesday! -wesley - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "Core Python Programming", Prentice Hall PTR, � 2001 http://starship.python.net/crew/wesc/cpp/ Silicon Valley-San Francisco Bay Area Python Users Group (BayPIGgies) http://deirdre.org/baypiggies wesley.j.chun :: wesc at deirdre.org cyberweb.consulting : henderson, nv : cyberweb at rocketmail.com http://www.roadkill.com/~wesc/cyberweb/

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Re: Sorting Instance Attributes, cont'd.
by Alan Colburn Feb. 10, 2003

Feb. 10, 2003

OK, I think I've got the relationship between cmp and sort. Thank you :-) I thought it was interesting to see the function in action, as Danny set it up. Sometimes it seems like the function didn't "do" what it was supposed to do, but grinding away comparison after comparison it did eventually give us a nice sorted list. And, since we're working at computer speeds, I guess "eventually" translates to nanoseconds :-) Moving on, then ... The simplest solution to my question looked like this: class Student(object): #Methods snipped. def __lt__(self, other): return self.lastname < other.lastname Tell me if I understand this next part correctly ... methods that begin with a double underscore are are "silent" and "private" to the class and its instances. In this case, we are overloading a method that's built into the class/instance, i.e., that's why you mean by "magic methods." Is that right? Further, "lt" is essentially an abbreviation for "less than," and that method will be run when we call __cmp__ ... which happens when we call sort() :-) So, when I try to sort() the objects (which are in a list), the overloaded __lt__ method is invoked and returns 1 when one lastname is before the other lastname, and that 1 is in turn used by the __cmp__ method. I'm still a little confused, but am I on the right track? __________________________________________________ Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now. http://mailplus.yahoo.com

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sorting into lists
by Tim Wilson Jan. 11, 2003

Jan. 11, 2003

Hey everyone, Let's say I've got a list like the following: l = [1, 1, 1, 2, 2, 3, 3, 3, 3, 4, 4] I'm trying to figure out a good way to turn this list into [[1, 1, 1], [2, 2], [3, 3, 3, 3], [4, 4]] Any ideas? -Tim -- Tim Wilson | Visit Sibley online: | Check out: Henry Sibley HS | http://www.isd197.org | http://www.zope.com W. St. Paul, MN | | http://slashdot.org wilson(a)visi.com | <dtml-var pithy_quote> | http://linux.com

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Do I need to have a strong math skills to program
by Dan Dud Jan. 10, 2003

Jan. 10, 2003

Hello everyone, Hope everyone weekend is going great. I working through the "how to think like a computer scientist" I'm stuck on the part which you have to define a hypotenuse triangle. I don't have a lot of math skills. Do I have to have a lot of math skills to be good at programming??? I've decided to skip that part and move on. I hope everyone weekend is going great and I'll talk to you all soon... Danny D _________________________________________________________________ Protect your PC - get McAfee.com VirusScan Online http://clinic.mcafee.com/clinic/ibuy/campaign.asp?cid=3963

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RE: [Tutor] Better (free) IDEs than IDLE for Linux ?
by alan.gauld＠bt.com Jan. 6, 2003

Jan. 6, 2003

> is graphical construction of the GUI - by drag and drop, The basic Unix toolset does not have a GUI builder because such things didn't exist when Unix was written, but several standalone GUI builders now exist which integrate admirably with Unix - both free and commercial. > Now, whether people consider that an advantage or not is > another thing I'm interested in. Its a big advantage for beginners and casual users but for experts its much faster to use a coding/resource file style of GUI creation. I'm told (by ex colleagues who work there) that several Microdsoft developers still maintain some of the Office GUI using the text form of the resource files.... Whether that's a recommendation is of course another matter! Personally I use Delphi on windows and Tkinter on Unix. I like both approaches. Tkinter is much more robust long term -it withstands window resizing etc better. But delphi is probably easier to draw ithe initial design. I have used SpecTcl and played with Glade under Unix too. > a very little bit of Win/C/SDK type development which is > similar to the UNIX approach that you describe, No, not at all! That really is stone age banging together of stones! Using a good high level class library makes it much easier. A more valid comparison would be using Swing/Awt in Java without a GUI builder. > etc. I think people would agree that this is a tedious and > error-prone approach to getting the GUI just right. If you know what you are doing and have *designed* the GUI in advance - something thats usually done by a separate human factors team using something like Visio on a big project - then the resource editor approach is very fast once you know the GUI "language" - somewhat similar to Tkinter programming (but using coordinates - yukk!) > that visual GUI construction can't be done without an IDE or > a GUI builder of some sort Of course it can - Microsoft Office was built entirely without GUI builders for the whole of its windows 3 lifetime. In fact most Windows 3 apops were built that way. Nearly all X Windows apps were built that way till the last few years - X has lagged in GUI builder tools. But I'd admit for a casual user its more difficult without a builder tool. > be separate - I believe Glade is something on those lines - > where it's mainly a GUI builder and can generate XML and/or > C/C++ code Correct, but its not an IDE. GUI builders are fine if thats what you like, but they are not *of necessity* IDEs. > I am, however, interested in knowing what others think - > those who done UI development (speaking both generally, about > any language/toolkit combination, and specifically about > Python-based GUI development) For heavyweight GUI development I tend to use a GUI builder but I know many GUI experts who don't. On Unix I tend to use one of the commercial products such as XVT or TeleUse. On Windows I use Delphi. But most of my Unix programming is not GUI based and so I don't need a GUI builder. A few admin screens, an app launcher, maybe an installer - all easily knocked together in Tkinter... > prefer") to design the UI purely via code ( Designing a GUI like any other kind of design is best done separately from the code that implements it. It should ideally be designed by someone who knows how users interact with computers. The programmers job is to take that designand turn it into code, ewither with tool support or by hand... Unfortunately one of the reasons so many bad GUI tools exist is that too many organisations leave GUI design to the programmers. (See "About Face" by Alan Cooper for examples) > for my present needs, as a relative beginner in GUI > development, I hadn't yet found the need for anything more > powerful or featureful. Sure, it actually sounds like your main need is a good GUI builder not necesarily an IDE per se... > Finally, as I said, I am not trying to criticize or start a > flame war - was just asking questions with a view to > learning. Me neither and in fact I am playing Devils advocate slightly. But many folks are unaware of just how powerful the raw Unix environment is. They jump straight into a GUI IDE without realizing that Unix can ber more powerful. And worse, they often criticize Unix for its lack of IDE when they don't understand that Unix is by design an IDE in its own right... > had not updated myself with vim's features as opposed to > traditional UNIX vi, hence didn't know that it could do all > that. I have an email friend who is a rabid emacs fan. He was bemoaning the fact he was forced to use vim at a recent job. Most of the things he thought were missing were in fact there - he hadn't used vi for 10 years.... Microsoft C IDE was pretty bad 10 years ago too! BTW I use both emacs and vim on Unix. ;-) Somebody else sent me mail(I think offline) showing some real advantages of IDEs, so in fairness I'll point out what I thought were valid ones: 1) Code completion - knowledge of the language allows suggestions of parameters etc. No editor, no matter how good the regex, is that smart. 2) Project management - GUI front ends for make exist, but IDEs can add some extra value here. 3) Syntax colouring - regex is OK but its possible to get confused. A full language parsing IDE can do a better job. So there are a few real advantages to IDEs, and thats fine provided you realize exactly what it is you are getting in real terms, and that equally Unix has a number of other features that the IDEs dont(yet) support... I'll make this my last word on this one :-) Alan g.

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2nd bonehead question...
by GREENDAY31087＠aol.com Jan. 5, 2003

Jan. 5, 2003

What is the difference(s) between py and pyc?

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RE: [Tutor] getting input from keyboard
by alan.gauld＠bt.com Jan. 5, 2003

Jan. 5, 2003

> How do I get keyboard input in python ? > I want to do the equivalent of this C code, in python > x=getch() Assuming you are on Windows you need to import mscvrt and use the getch() function in there. If you are on Unix you use the curses(or ncurses) module which also has a getch() function. > With the books that I have, there are no references in the > index to get, keyboard input, or in the Python help file. My online web tutor (and book!)has a topic on event driven programming which includes an example of using msvcrt.getch() Alan g. Author of the 'Learning to Program' web site http://www.freenetpages.co.uk/hp/alan.gauld

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Declare empty string variable?
by Volker Hoffmann Jan. 2, 2003

Jan. 2, 2003

Hi, at first I just want to say hi. I've been reading on digests for a couple of months (rather irregularily though) as I didn't have much time for getting into python. Now I have some spare time and I'm gonna be starting of with a possible stupid question :-). I want to write a program that converts decimal numbers into binary format. That should be a fairly easy task, but not with my limited knowledge of python. Here's how my code looks so far: > ### Decimal to Binary Conversion > deci=input("Decimal? --> ") > dual= <--- declaration > ... > while deci>0: > dual_tmp=deci%2 > dual=dual_tmp, dual <--- change dual here > deci=deci/2 > print "Binary is", dual Now I want the variable "dual" to be the output where the binary is being stored. However, since I assume that all variables have to be initialized in python I don't have any clue HOW to make dual a string variable that's being updated every time in the while-loop. Now, how do I have to declare "dual" to be a string and without any value at the beginning? Is there any way like in pascal where it's beging declared like this: > var > dual:string; Thanks in advance, - Volker -- "Earth is the cradle of mankind, but one cannot live in the cradle forever." - Konstantin Tsiolkovsky

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How can i dump the DB data into a text file in CSV format
by shobhan Jan. 2, 2003

Jan. 2, 2003

Hi Pythoners, Can anyone tell me how to connect to Oracle DB using Python and dump the data from a table called "logs" into a text file in CSV format..? The text file thus created should be of the format (2002-12-30-logs.txt). It would be fine if anyone can show a sample script. Thanks in advance Schalla

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