ArrayAccess::offsetExists

(PHP 5, PHP 7, PHP 8)

ArrayAccess::offsetExistsWhether an offset exists


Description

abstract public ArrayAccess::offsetExists ( mixed $offset ) : bool

Whether or not an offset exists.

This method is executed when using isset() or empty() on objects implementing ArrayAccess.

Note:

When using empty() ArrayAccess::offsetGet() will be called and checked if empty only if ArrayAccess::offsetExists() returns TRUE.

Parameters

offset
An offset to check for.


Return Values

Returns TRUE on success or FALSE on failure.

Note:

The return value will be casted to bool if non-boolean was returned.

Examples

Example #1 ArrayAccess::offsetExists() example

<?phpclass obj implements arrayaccess {    public function offsetSet($offset, $value) {        var_dump(__METHOD__);    }    public function offsetExists($var) {        var_dump(__METHOD__);        if ($var == "foobar") {            return true;        }        return false;    }    public function offsetUnset($var) {        var_dump(__METHOD__);    }    public function offsetGet($var) {        var_dump(__METHOD__);        return "value";    }}$obj = new obj;echo "Runs obj::offsetExists()\n";var_dump(isset($obj["foobar"]));echo "\nRuns obj::offsetExists() and obj::offsetGet()\n";var_dump(empty($obj["foobar"]));echo "\nRuns obj::offsetExists(), *not* obj:offsetGet() as there is nothing to get\n";var_dump(empty($obj["foobaz"]));?>

The above example will output something similar to:


Runs obj::offsetExists()
string(17) "obj::offsetExists"
bool(true)

Runs obj::offsetExists() and obj::offsetGet()
string(17) "obj::offsetExists"
string(14) "obj::offsetGet"
bool(false)

Runs obj::offsetExists(), *not* obj:offsetGet() as there is nothing to get
string(17) "obj::offsetExists"
bool(true)