[Tutor] Fastest way to iterate through a file

[Robert Hicks]

Kent Johnson wrote:
> Robert Hicks wrote:
>> Kent Johnson wrote:
>>> Robert Hicks wrote:
>>>> idList only has about 129 id numbers in it.
>>> That is quite a few times to be searching each line of the file. Try 
>>> using a regular expression search instead, like this:
>>>
>>> import re
>>> regex = re.compile('|'.join(idList))
>>> for line in f2:
>>>    if regex.search(line):
>>>      # process a hit
>>>
>> Since I am printing to a file like so:
>>
>> [id]: [line]
>>
>> I don't see how I can get the id back out of the regex.search like I 
>> could in my code.
> 
> match = regex.search(line)
> if match:
>    idMatch = match.group()
>    print idMatch, line
> 
> Note this will only find the first id match on a line. If you need to 
> find multiple matches per line use findall() or finditer() as Dave suggests.
> 
> re docs are here:
> http://docs.python.org/lib/module-re.html
> 

I was just reading that.  : )

That worked...and while the first one was probably "good" enough, I have 
learned something new today thanks to you and the others.

TYVM

Robert