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@salimane salimane/gist:8958411
Last active Aug 29, 2015

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ruby slow regex match
salimane at Salimanes-MacBook-Pro in ~
⚛ ruby --version
ruby 2.1.0p0 (2013-12-25 revision 44422) [x86_64-darwin13.0]
salimane at Salimanes-MacBook-Pro in ~
⚛ cat regex.rb
regex = %r{^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$}
link = "https://www.facebook.com/DUSA.ve?ref=stream"
puts link =~ regex
salimane at Salimanes-MacBook-Pro in ~
time ruby regex.rb
ruby regex.rb 114.95s user 0.11s system 99% cpu 1:55.07 total
salimane at Salimanes-MacBook-Pro in ~
⚛ php -v
PHP 5.4.17 (cli) (built: Aug 25 2013 02:03:38)
Copyright (c) 1997-2013 The PHP Group
Zend Engine v2.4.0, Copyright (c) 1998-2013 Zend Technologies
salimane at Salimanes-MacBook-Pro in ~
⚛ cat regex.php
<?php
$regex = '/^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$/';
$link = "https://www.facebook.com/DUSA.ve?ref=stream";
echo preg_match($regex, link);
salimane at Salimanes-MacBook-Pro in ~
time php regex.php
0php regex.php 0.07s user 0.01s system 96% cpu 0.079 total
salimane at Salimanes-MacBook-Pro in ~
⚛ java -version
java version "1.7.0_21"
Java(TM) SE Runtime Environment (build 1.7.0_21-b12)
Java HotSpot(TM) 64-Bit Server VM (build 23.21-b01, mixed mode)
salimane at Salimanes-MacBook-Pro in ~
⚛ cat Regex.java
public class Regex {
public static void main(String[] args) {
String regex = "^(https?://)?([\\da-z.-]+).([a-z.]{2,6})([/\\w .-]*)*/?$";
String link = "https://www.facebook.com/DUSA.ve?ref=stream";
System.out.println(link.matches(regex));
}
}
salimane at Salimanes-MacBook-Pro in ~
⚛ javac Regex.java
salimane at Salimanes-MacBook-Pro in ~
time java Regex
false
java Regex 0.75s user 0.04s system 136% cpu 0.584 total
salimane at Salimanes-MacBook-Pro in ~
⚛ python --version
Python 2.7.3
salimane at Salimanes-MacBook-Pro in ~
⚛ cat regex.py
import re
regex = r'^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$'
link = "https://www.facebook.com/DUSA.ve?ref=stream"
print re.match(regex, link)
salimane at Salimanes-MacBook-Pro in ~
time python regex.py
Traceback (most recent call last):
File "regex.py", line 4, in <module>
print re.match(regex, link)
File "/opt/boxen/homebrew/Cellar/python/2.7.3-boxen2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 137, in match
return _compile(pattern, flags).match(string)
File "/opt/boxen/homebrew/Cellar/python/2.7.3-boxen2/Frameworks/Python.framework/Versions/2.7/lib/python2.7/re.py", line 242, in _compile
raise error, v # invalid expression
sre_constants.error: nothing to repeat
python regex.py 0.02s user 0.01s system 43% cpu 0.079 total
@hughdbrown

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hughdbrown commented Feb 12, 2014

Using python 2.7.5, I get no match on this regex.

>>> import re
>>> regex = r'^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$'
>>> link = "https://www.facebook.com/DUSA.ve?ref=stream"
>>> print re.match(regex, link)
None

I do get a match on this:

>>> import re
>>> regex = r'^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?.*$'
>>> link = "https://www.facebook.com/DUSA.ve?ref=stream"
>>> print re.match(regex, link)
<_sre.SRE_Match object at 0x7fb2bf8bcb58>
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