preg_replace_callback()

preg_replace_callback() — Perform a regular expression search and replace using a callback.

preg_replace_callback() — The behavior of this function is almost identical to preg_replace, except for the fact that instead of replacement parameter, one should specify a callback.

Inputs: pattern: The pattern to search for. It can be either a string or an array with strings. callback: A callback that will be called and passed an array of matched elements in the subject string. The callback should return the replacement string. This is the callback signature: stringhandler arraymatches subject: The string or an array with strings to search and replace. limit: The maximum possible replacements for each pattern in each subject string. Defaults to -1 (no limit).

Returns: preg_replace_callback returns an array if the subject parameter is an array, or a string otherwise. On errors the return value is null If matches are found, the new subject will be returned, otherwise subject will be returned unchanged.