3v4l.org

run code in 150+ php & hhvm versions
Bugs & Features
<?php var_dump(preg_replace('/(?<=[a-z])([A-Z])\L/', '_$1', 'AnaNaaZ'));
based on 5CknE
Output for 5.3.4 - 7.1.0
Warning: preg_replace(): Compilation failed: PCRE does not support \L, \l, \N{name}, \U, or \u at offset 18 in /in/TKHcZ on line 3 NULL
Output for 4.4.0 - 4.4.9, 5.0.5 - 5.3.3
Warning: preg_replace(): Compilation failed: PCRE does not support \L, \l, \N, \U, or \u at offset 18 in /in/TKHcZ on line 3 NULL
Output for 4.3.11, 5.0.0 - 5.0.4
Warning: preg_replace(): Compilation failed: PCRE does not support \L, \l, \N, \P, \p, \U, \u, or \X at offset 18 in /in/TKHcZ on line 3 NULL
Output for 4.3.0 - 4.3.10
Warning: Compilation failed: PCRE does not support \L, \l, \N, \P, \p, \U, \u, or \X at offset 18 in /in/TKHcZ on line 3 NULL