[Tutor] performance considerations

dman dsh8290@rit.edu
Mon, 3 Dec 2001 13:31:13 -0500

On Mon, Dec 03, 2001 at 01:10:41PM -0500, Andrei Kulakov wrote:
| On Mon, Dec 03, 2001 at 12:51:39PM -0500, dman wrote:
| > 
| > I'm working on a script/program to do some processing (munging) on
| > text files in a directory tree.  In addition, for convenience, all
| > non-interesting files are copied without munging.  My script, as it
| > stands, is quite CPU intensive so I would like to optimize it some.
| > 
| > In the case of copying non-interesting files, what is (generally) the
| > most efficient way?  It seems there is no system-level "copy" command.
| shutil.copy()

Cool, thanks.

| > A portion of the script generates strings by starting with 'a' and
| > "adding" to it.  Ie "a", "b", ..., "z", "aa", "ab", ..., "zz", "aaa".
| > Would it be better to use a list of one-char-strings than to modify a
| > single string?  Here's the code I have now (BTW, that funny-looking

I forgot to mention, if a list of strings is used, each yield will
yield  "".join( the_list ), so the comparison is the multiple
modifications (creation) of strings versus join.

| I believe so.. profile!

I should.

| > One last question for now :
| > I traverse the interesting files line-by-line and check them for a
| > regex match, then modify the line if it matches properly.  Would it be
| > better (faster) to read in the whole file and treat it as a single
| > string?  Memory is not a problem.
| Yeah, probably.. profile!

I want to speculate before I rewrite it :-).  Maybe Tim will tell me
something (since he is so familiar with the inner workings)?



How to shoot yourself in the foot with Java:

You find that Microsoft and Sun have released imcompatible class
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languages, you cannot get access to one. But seeing as Java is so cool,
you dont care and go around shooting anything else you can find.
    (written by Mark Hammond)