Variables doubleval Get double value of a variable. double doubleval mixed var Returns the double (floating point) value of var. var may be any scalar type. You cannot use doubleval on arrays or objects. See also intval, strval, settype and Type juggling. empty determine whether a variable is set int empty mixed var Returns false if var is set and has a non-empty or non-zero value; true otherwise. See also isset and unset. gettype Get the type of a variable. string gettype mixed var Returns the type of the PHP variable var. Possibles values for the returned string are: "integer" "double" "string" "array" "object" "unknown type" See also settype. intval Get integer value of a variable. int intval mixed var int base Returns the integer value of var, using the specified base for the conversion (the default is base 10). var may be any scalar type. You cannot use intval on arrays or objects. See also doubleval, strval, settype and Type juggling. is_array Finds whether a variable is an array. int is_array mixed var Returns true if var is an array, false otherwise. See also is_double, is_float, is_int, is_integer, is_real, is_string, is_long, and is_object. is_double Finds whether a variable is a double. int is_double mixed var Returns true if var is a double, false otherwise. See also is_array, is_float, is_int, is_integer, is_real, is_string, is_long, and is_object. is_float Finds whether a variable is a float. int is_float mixed var This function is an alias for is_double. See also is_double, is_real, is_int, is_integer, is_string, is_object, is_array, and is_long. is_int Find whether a variable is an integer. int is_int mixed var This function is an alias for is_long. See also is_double, is_float, is_integer, is_string, is_real, is_object, is_array, and is_long. is_integer Find whether a variable is an integer. int is_integer mixed var This function is an alias for is_long. See also is_double, is_float, is_int, is_string, is_real, is_object, is_array, and is_long. is_long Finds whether a variable is an integer. int is_long mixed var Returns true if var is an integer (long), false otherwise. See also is_double, is_float, is_int, is_real, is_string, is_object, is_array, and is_integer. is_object Finds whether a variable is an object. int is_object mixed var Returns true if var is an object, false otherwise. See also is_long, is_int, is_integer, is_float, is_double, is_real, is_string, and is_array. is_real Finds whether a variable is a real. int is_real mixed var This function is an alias for is_double. See also is_long, is_int, is_integer, is_float, is_double, is_object, is_string, and is_array. is_string Finds whether a variable is a string. int is_string mixed var Returns true if var is a string, false otherwise. See also is_long, is_int, is_integer, is_float, is_double, is_real, is_object, and is_array. isset determine whether a variable is set int isset mixed var Returns true if var exists; false otherwise. If a variable has been unset with unset, it will no longer be isset. $a = "test"; echo isset($a); // true unset($a); echo isset($a); // false See also empty and unset. settype Set the type of a variable. int settype string var string type Set the type of variable var to type. Possibles values of type are: "integer" "double" "string" "array" "object" Returns true if successful; otherwise returns false. See also gettype. strval Get string value of a variable. string strval mixed var Returns the string value of var. var may be any scalar type. You cannot use strval on arrays or objects. See also doubleval, intval, settype and Type juggling. unset Unset a given variable int unset mixed var unset destroys the specified variable and returns true. unset( $foo ); unset( $bar['quux'] ); See also isset and empty.