extracting a substring

[Gary Herron]

b83503104 at yahoo.com wrote:

>Hi,
>I have a bunch of strings like
>a53bc_531.txt
>a53bc_2285.txt
>...
>a53bc_359.txt
>
>and I want to extract the numbers 531, 2285, ...,359.
>
>One thing for sure is that these numbers are the ONLY part that is
>changing; all the other characters are always fixed.
>
>I know I should use regular expressions, but I'm not familar with
>python, so any quick help would help, such as which commands or idioms
>to use.  Thanks a lot!
>
>  
>
Try this:

 >>> import re
 >>> pattern = re.compile("a53bc_([0-9]*).txt")
 >>>
 >>> s = "a53bc_531.txt"
 >>> match = pattern.match(s)
 >>> if match:
... print int(match.group(1))
... else:
... print "No match"
...
531
 >>>

Hope that helps,
Gary Herron