Data type
Integer
Floating point type
Boolean type
String
Array
Object
Conversion between types
(int)$val; Convert to integer type
(float)$val; Convert to floating point type
( string)$val; Convert to string
(bool)$val; Convert to Boolean type
(array)$val; Convert to array, the array only contains one element $val. [$val]
(object)$val; Convert to an object, the scalar attribute of the object points to $val. {scalar:$val}
Get the type
Use the function string gettype($val); to get the variable type
The return value of this function is array, boolean, double, integer, object, resource, string, NULL and unknown type.
In addition, you can also use the following functions to determine the variable type
is_array(val); is_bool(val); is_float(val); is_integer(val); is_null(val); is_numeric(val); is_object(val); is_resource(val) ; is_scalar(val); and is_string(val);
PHP super global variable
$_SERVER Contains browser and server related data
$_GET Contains GET data in url request
$_POST Contains POST data in url request
$_COOKIE Contains browser COOKIE data
$_SESSION Used to access SESSION data
$_FILES Contains file upload data
$GLOBALS Contains all global variables
The above introduces PHP data types and conversions, including data types and PHP content. I hope it will be helpful to friends who are interested in PHP tutorials.