(PHP 4 >= 4.0.5, PHP 5, PHP 7) Locale based string comparison

(PHP 4, PHP 5, PHP 7) Calculate the md5 hash of a string

(PECL ssdeep >= 1.0.0) Create a fuzzy hash from a file

(PHP 5, PHP 7) Convert a string to an array array

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Return information about words used in a string

(PHP 4 >= 4.0.1, PHP 5) Split string into array by regular expression case insensitive

(PHP 5, PHP 7) Binary safe comparison of two strings from an offset, up to length characters

(PHP 4, PHP 5, PHP 7) Strip whitespace (or other characters) from the beginning and end of a string

(PHP 4, PHP 5, PHP 7) Un-quotes a quoted string

(PHP 4, PHP 5, PHP 7) Strip whitespace (or other characters) from the end of a string