(PHP 4, PHP 5, PHP 7) Prints human-readable information about a variable

(PECL quickhash >= Unknown) This method adds a new entry to the set

(PHP 5 >= 5.1.0, PHP 7) Checks if the object or class has a property

(PHP 4, PHP 5, PHP 7) Import variables into the current symbol table from an array

(PHP 4, PHP 5, PHP 7) Sort an array using a "natural order" algorithm