(PHP 5 >= 5.2.0, PHP 7) Filters a variable with a specified filter

(PHP 4, PHP 5, PHP 7) Set the internal pointer of an array to its first element

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Checks if the object is of this class or has this class as one of its parents

(PHP 5 >= 5.2.0, PHP 7) Gets a specific external variable by name and optionally filters it

(PHP 4, PHP 5, PHP 7) Pad array to the specified length with a value

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Check for alphanumeric character(s)

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Outputs or returns a parsable string representation of a variable

(PHP 5, PHP 7) Gets property name public string

(PHP 5, PHP 7) Checks if user defined public

(PHP 4, PHP 5, PHP 7) Returns an array with the name of the defined classes