Function Description
is_array() Returns true if the argument is an array
is_bool() Returns true if the argument is boolean
is_double() Returns true if the argument is a double
is_int() Returns true if the argument is an integer
is_object() Returns true if the argument is an object
is_string() Returns true if the argument is a string
is_null() Returns true if the argument is null
is_resource() Returns true if the argument is a resource