I've got the two following snippets:

PERL:

my $fn = shift;
exit 1 if not defined $fn;

my $input = do {
    open my $fh, "<", $fn or die "open failed";
    local $/;
    <$fh>
};

my $count = () = $input =~ m/mul\(\d{1,3},\d{1,3}\)/g;

print "Found $count matches.\n";

[download]

PYTHON:

import re
import sys

if len(sys.argv) < 2: exit(1)

mul_re = re.compile(r"mul\(\d{1,3},\d{1,3}\)")

with open (sys.argv[1], "r") as f:
    input = f.read()

count = len(mul_re.findall(input))

print(f"Found {count} matches.")

[download]

Which do more or less the same thing. Running both scripts on the same file, I found that the Python version runs a full second faster! 1.375s as opposed to Perl's 2.466s

I had always thought that Perl's regex and parsing performance was particularly strong compared to other languages, so this was a shocker for me. What is it that I am doing wrong? How can I make the Perl version run as fast as the one in Python?

Thanks. -- Dave

In reply to Python regex faster than Perl? by dave93

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.