(PHP 4, PHP 5) Split string into array by regular expression

(PHP 4, PHP 5, PHP 7) Convert from one Cyrillic character set to another

(PHP 4, PHP 5, PHP 7) Join array elements with a string

(PHP 4, PHP 5, PHP 7) Translate characters or replace substrings

(PHP 4, PHP 5, PHP 7) Quote meta characters string

(PHP 4, PHP 5, PHP 7) Calculate the similarity between two strings

(PHP 4, PHP 5, PHP 7) Convert all applicable characters to HTML entities

(PHP 5, PHP 7) Uuencode a string string convert_uuencode

(PHP 4, PHP 5, PHP 7) Output one or more strings

(PHP 4 >= 4.0.1, PHP 5, PHP 7) Parses input from a string according to a format