I did some crude benchmarking and the only speedups for your regex I could find were:

  1. Anchor the end of the regex with a $. 2-3%
  2. Don't capture the inner group, use (?:\S+\s+) 3-4%
  3. use study on $line before the if() statement 2-3%

A total benefit of 8-9% timing the match/assignment only, and I could only measure the changes by repeating the matching/assignment 1000 times for each line! Overall, not a great deal to be gained. For instance, just including the four print statements into the timing, even when redirecting the output to the null device, increased the time taken to process each line by 300%. Making the small savings I described above <1% in total.

You would gain more by

Whatever differences the changes I described make, they are likely to pale into insignificance when compared to whatever you are doing with the data you have extracted from each line. Even just writing this to another file will completely marginalise any savings.


Okay you lot, get your wings on the left, halos on the right. It's one size fits all, and "No!", you can't have a different color.
Pick up your cloud down the end and "Yes" if you get allocated a grey one they are a bit damp under foot, but someone has to get them.
Get used to the wings fast cos its an 8 hour day...unless the Govenor calls for a cyclone or hurricane, in which case 16 hour shifts are mandatory.
Just be grateful that you arrived just as the tornado season finished. Them buggers are real work.


In reply to Re: Efficient Log File Parsing with Regular Expressions by BrowserUk
in thread Efficient Log File Parsing with Regular Expressions by hackdaddy

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