🌐 Mailman 3 September 2000 - Python-list - python.org

Python Strings
by CHRIS Sept. 30, 2000

Sept. 30, 2000

How can you make a character-by-character copy of one string to a target string, with out using a temporary list type variable? IE (with out doing somethin like this): fromstr = 'aslfdj'; target = []; for i in range(len(fromstr)): #procssing done here target.append(fromstr[i]); Also, what's the point of strings being immutable ?? If you want a particular variable to be immutable, why not have some sort of constant option? Like in C: static const char str[] = "Constant immutable string";

17 41

cxx on python 2.0
by olczyk＠interaccess.com Sept. 30, 2000

Sept. 30, 2000

Has anyone tried using cxx with Python2.0 yet?

1 0

Another newbie question
by Prospero Sept. 30, 2000

Sept. 30, 2000

Greetings! Firstly, thanks to all who answered my first question. After four days playing with Python I know more about it than I do about Java after as many months. My new question has to do with files. I am working on a project which will involve several very large files of grouped integers. I can see how to create the files as text and convert to and from integers but surely there must be a better solution than this. I have tried the tutorials and what example files I can find, so far without success. Can someone point me in the right direction? All the best, Prospero. "Never be bullied into silence. Never allow yourself to be made a victim. Accept no one's definition of your life; define yourself." --Harvey Fierstein Prospero's World: http://www.bigwig.net/prospero

1 0

Re: Fractal Dimension Computation in Python Code
by Alex Sept. 30, 2000

Sept. 30, 2000

> Myk> ... Has anyone got a fast routine for calculating the fractal > dimension of a set of points in 2 or 3D space? Thanks. > > According to the inventor of fractals (Hausdorff in the year 1899), > you can place the set of 2D points next to a wall and shine light > through them, and the fractal dimension is the percentage of shadow on > the wall. Can you give a reference? This suprises me, because it seems to me that since a Koch-curve has zero two-dimensional area, it will also cast a zero-area shadow. On the other hand, its Hausdorff dimension is greater than 1, if I recall correctly. Is Hausdorff dimension the same as fractal dimension? Alex. -- Speak softly but carry a big carrot.

5 7

Re: Possible 2.0b2 bug: Recursion limit in non-greedy regular expressions
by Darrell Gallion Sept. 30, 2000

Sept. 30, 2000

I posted a patch. Although I'm sure the patch will need some work, it solved only my immediate need. Suspect this error might still occur with other patterns. Here's a solution, hopefully posting these won't get me into trouble :) http://dorb.com/darrell/dropPoint/_sre.pyd http://dorb.com/darrell/dropPoint/_sre.c --Darrell From: "Richie Hindle" > longish strings. If I run the following code in 2.0b2: > > >>> re.match( 'a.*?b', 'a' + 'c' * 16167 ) > > it fails with "RuntimeError: maximum recursion limit exceeded". > Decreasing the number of 'c's to 16166 makes it OK. >

1 0

Tk from IDLE: How to 'Hello World'?
by Kirby Urner Sept. 30, 2000

Sept. 30, 2000

Tk in Windows IDLE does not work the way tutorials suggest. For example, consider Fredrik Lundh's 'Hello World' app at http://www.pythonware.com/library/tkinter/introduction/hello-tkinter.htm Writing it interactively in IDLE, one would go: >>> from Tkinter import * >>> def test(): root = Tk() w = Label(root, text="Hello, world!") w.pack() root.mainloop() >>> test() Which gets you the Tk window saying Hello World, as expected. But then if you hit the close box, do you get back to a working IDLE prompt? I don't. I'm left in limbo, with a prompt I can't go back to. I haven't tested this in LINUX IDLE yet, nor in 1.5.2 -- so maybe this is a new phenomenon with the latest beta? Or is it some problem with my setup? Could another Windows user provide a reality check here? Anyway, Lundh's book and many other resources do not appear to be written with IDLE in mind. For example it states: To run the program, run the script as usual: $ python hello1.py But that's not 'usual' for an IDLE user. There's no $ prompt, and we're already in Python, and so wouldn't invoke it. As someone interested in using Python in schools, I think a GUI like IDLE is a potentially better learning environment than a command line in DOS or Xterm. I would like to see more bias in favor of using IDLE when doing work with Tk (IDLE being itself a Tk app, after all, and cross-platform). Kirby

2 3

basic python threading question
by Tom Sept. 30, 2000

Sept. 30, 2000

I decided to give a thread its own copy of some data. But I gather that it is impossible to create a seperate copy of an atomic object (because the implementation is free to make both names bind to the same object). This would be a problem for threading, unless all atomic objects are thead-safe. Now, all atomic objects appear to me to be immutable. Are immutable objects inherently thread-safe in Python (even if the ref count change)? Thanks, Tom.

6 14

How to accumulate a matrix in a loop efficiently
by hzhu＠users.sourceforge.net Sept. 30, 2000

Sept. 30, 2000

This is a NumPy question: Say I have a loop that gives me a one dim array at a time. What would be the most efficient way to accumulate it? Is the following a good way to do it? >>> from Numeric import * >>> a = [] >>> for i in range(3): a.append(arange(5)) ... >>> array(a) array([[0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4]]) What if I get a (1, n) shaped array at each step? Huaiyu -- Huaiyu Zhu hzhu(a)users.sourceforge.net Matrix for Python Project http://MatPy.sourceforge.net

1 0

How to accumulate a matrix in a loop efficiently
by hzhu＠users.sourceforge.net Sept. 30, 2000

Sept. 30, 2000

This is a NumPy question: Say I have a loop that gives me a one dim array at a time. What would be the most efficient way to accumulate it? Is the following a good way to do it? >>> from Numeric import * >>> a = [] >>> for i in range(3): a.append(arange(5)) ... >>> array(a) array([[0, 1, 2, 3, 4], [0, 1, 2, 3, 4], [0, 1, 2, 3, 4]]) What if I get a (1, n) shaped array at each step? Huaiyu -- Huaiyu Zhu hzhu(a)users.sourceforge.net Matrix for Python Project http://MatPy.sourceforge.net

1 0

Sum of the Least Squares
by Gene C Sept. 30, 2000

Sept. 30, 2000

Hi, Does anyone know where I can find a function to do non-linear least squares fit interpolation that is implemented in python? (actual python code, not a module implemented in something else) Other curve fitting functions would be interesting too. Thanks, Gene ps - I tried the vaults, but sadly it's down.

4 6