Comments on: Powerful PHP: Less Known String Manipulation

By: Gary Hvizdak

Gary Hvizdak — Sat, 24 Aug 2013 13:19:23 +0000

Tom says:
August 18, 2011 at 5:06 pm

Also, when checking if a string is longer then, let’s say 32 characters, if($str[33]) is faster then if (strlen($str) > 32)!

Yikes! This isn’t binary safe! What if the 33 byte is a binary zero?

By: Steve

Steve — Sat, 07 Apr 2012 03:26:46 +0000

substr($s, 0, 1) and $s[0] give you the first byte, which may not be a complete character. $s = “ɥello”;

By: Jim O'Halloran

Jim O'Halloran — Tue, 23 Aug 2011 23:52:07 +0000

@Tom – The @ (error suppression) operator has some performance overhead, even more so if it actually needs to suppress an error. See http://seanmonstar.com/post/909029460/php-error-suppression-performance for more info.

By: Tom

Tom — Fri, 19 Aug 2011 07:13:54 +0000

@Jason Ok, I double checked it it just to be sure. I found some interesting things actually.

The $str[33] method is faster. But, as you mentioned, It’ll give you a notice if the string is shorter. So you want to put a @ in front of it to ignore that notice.. But this actually makes it slower for some reason! Even if you don’t produce an error!

My test:
String: ‘abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz’;
length: 52

strlen(): 0.784919977188…
[] : 0.502612113953…
@[] : 1.37400698662…!!
{} : 0.206066131592…

By: Jason

Jason — Thu, 18 Aug 2011 22:42:54 +0000

That will also throw a warning if the key does not exist.

if(array_key_exists(33, (array)$string)){ … }

I’m not convinced that if($string[33]) … is faster than if(strlen($string) > 32) { … }

By: Stoimen

Stoimen — Thu, 18 Aug 2011 14:08:04 +0000

@Tom – Great! Thanks!

By: Tom

Tom — Thu, 18 Aug 2011 14:06:44 +0000

You can also do this with de []’s, like: $str[0];

Also, when checking if a string is longer then, let’s say 32 characters, if($str[33]) is faster then if (strlen($str) > 32)!