Comments on: The Joy of Regular Expressions [2]

By: HarryF

HarryF — Mon, 21 Jan 2008 20:07:46 +0000

if the filename has dots as separators in it the regexp won’t work

It would still work : /^.*\.jpe?g$/i - all I'm doing there is requiring the filename ends with .jpg or .jpeg (case insenstive). otherwise you're allowed anything you like including . characters.

By: Päse

Päse — Mon, 21 Jan 2008 15:07:45 +0000

Nice examples! But you should check your “Hunting for .jp(e)g” because if the filename has dots as separators in it the regexp won’t work ;-)

By: asdasdasd

asdasdasd — Tue, 07 Nov 2006 22:42:38 +0000

What’s interesting is str_replace performs better in this case, but only significantly so if the “replace” target is a string—not an array

By: HarryF

HarryF — Fri, 27 Oct 2006 21:09:41 +0000

Great article, and thanks for the bit on eval()—I never knew of its security flaws over and above the obvious injection attacks.

By the way, the link to sprintf() on php.net is incorrect here—it links to http://php.nett/sprintf.

Thanks and thanks – now fixed at last.

By: Sean

Sean — Fri, 29 Sep 2006 14:59:49 +0000

Great article, and thanks for the bit on eval() – I never knew of its security flaws over and above the obvious injection attacks.

By the way, the link to sprintf() on php.net is incorrect here – it links to http://php.nett/sprintf.

By: 1magic

1magic — Wed, 27 Sep 2006 15:01:11 +0000

Nice article series. Thanks!

By: Selkirk

Selkirk — Wed, 27 Sep 2006 14:53:22 +0000

Nice article. There is also another problem with escaping the replacement parameter of preg_replace under certain conditions. preg_quote is not suitable for that task because it is geared toward the search parameter and not the replacement parameter. I talk about that and the e modifier in my blog post on preg_replace escaping.

By: HarryF

HarryF — Wed, 27 Sep 2006 10:08:14 +0000

Harry, didn't you mean str_replace?

Well I meant strtr() (the example works) based on the unconfirmed theory that it would offer better performance than str_replace(). But looking at this (see str_replace vs. strtr later on) reminds me it's best always to question "accepted performance wisdom" with benchmarks. What's interesting is str_replace performs better in this case, but only significantly so if the "replace" target is a string - not an array Fastest: $str = str_replace(array( "\r\n","\n"), "\n", $str); About the same: $str = str_replace(array( "\r\n","\n"), array("\n","\n"), $str); $str = strtr($str, array( "\r\n"=>"\n" , "\r"=>"\n" )); Even more excitement - doing two seperate strtr's seems to match the performance of the fastest str_replace above;


$str = strtr($str, "\r\n", "\n");
$str = strtr($str, "\r", "\n");

...but used pretty short $str's so that may not scale to bigger documents. Side note: additional confusion is being caused in these examples by the comment feature adding slashes to quotes :(

By: Maarten Manders

Maarten Manders — Wed, 27 Sep 2006 09:29:10 +0000

The replacement doesn’t need to be an array, just “\n”, if i remember correctly.

By: Maarten Manders

Maarten Manders — Wed, 27 Sep 2006 09:28:12 +0000

Harry, didn't you mean str_replace? For normalization we're using

  
str_replace(array("\r\n", "\r"), array("\n", "\n"), $input)