(PHP 4 >= 4.0.2, PHP 5, PHP 7) Binary safe case-insensitive string comparison of the first n characters

(PHP 4, PHP 5, PHP 7) Get string length int strlen

(PHP 4, PHP 5, PHP 7) Quote regular expression characters

(PHP 4, PHP 5, PHP 7) Find the position of the first occurrence of a substring in a string

(PHP 4, PHP 5, PHP 7) Returns the translation table used by htmlspecialchars()

(PHP 4, PHP 5, PHP 7) Replace all occurrences of the search string with the replacement string

(PHP 4, PHP 5, PHP 7) One-way string hashing