Concerning Regular Expressions

Alex Martelli aleax at mail.comcast.net
Mon Jan 30 05:44:57 CET 2006


Tempo <bradfordh at gmail.com> wrote:

> I've been reading a bunch of articles and tutorials on the net, but I
> cannot quite get ahold of the whole regular expression process. I have
> a list that contains about thirty strings, each in its own spot in the
> list. What I want to do is search the list, say it's called 'lines',
> for 'R0 -'.

No need for regular expressions for this task as you expressed it:

  for aline in lines:
    if 'R0 -' in aline:
       doyourworst(aline)

I've sweated substantial amount of blood and other bodyfluiids trying to
explain "the whole regular expresson process" concisely and effectively
in chapter 9 of "Python in a Nutshell" (and I'm going through the
heartache of preparing the second edition now -- let's say I'm currently
grasping for any straw to avoid the work;-) -- if I didn't do a good
enough job there, I sure can't do better here.  But one thing stands: if
you don't yet understand fully the abilities of Python's strings and
other builtins, as for example in the above snippet, studying REs is
premature.  WAY premature.


Alex



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