Bryant Huang wrote:
> Is it possible to perform iteration within the re.sub() function call?
>
> For example, if I have a string like:
>
> str = "abbababbabbaaa"
>
> and I want to replace all b's with an integer that increments from 0,
> could I do that with re.sub()?
>
> Replacing b's with 0's is trivial:
>
> i = 0
> pat = re.compile("b")
> print pat.sub(`i`, str)
>
> Now, how can I increment i in each replacement? Is this
> possible? Like,
> using a lambda function, for example? Or do I use a different re
> function altogether?
>
> I use this trivial [ab]* language for simplicity, but I have a real
> problem where I need to match a more complex regex and replace it with
> an incrementing integer.
It's possible. Here's a quick, ugly version, which:
1. Uses a function for the "repl" arg of re.sub().
2. Uses a list to get around i being local inside of sub(). You could
just as well use the global statement.
3. Starts i[0] at -1. You could also use itertools.count or range to
good effect.
PythonWin 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)]
on win32.
>>> import re
>>> s = "abbababbabbaaa"
>>> i[0] = -1
>>> def sub(match):
... i[0] += 1
... return str(i[0])
...
>>> re.sub("b", sub, s)
'a01a2a34a56aaa'
Robert Brewer
MIS
Amor Ministries
[EMAIL PROTECTED]
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