ArrayAccess
PHP Manual

ArrayAccess::offsetExists

(PHP 5 >= 5.0.0)

ArrayAccess::offsetExistsWhether a offset exists

Descrizione

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

Whether or not an offset exists.

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

Nota:

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

Elenco dei parametri

offset

An offset to check for.

Valori restituiti

Restituisce TRUE in caso di successo, FALSE in caso di fallimento.

Nota:

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

Esempi

Example #1 ArrayAccess::offsetExists() example

<?php
class 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"]));
?>

Il precedente esempio visualizzerĂ  qualcosa simile a:

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)


ArrayAccess
PHP Manual