(PHP 5, PHP 7, PHP 8)
ArrayAccess::offsetExists — Whether an offset exists
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.
offsetAn offset to check for.
Returns true on success or false on failure.
Note:
The return value will be casted to bool if non-boolean was returned.
Example #1 ArrayAccess::offsetExists() example
<?php
class obj implements ArrayAccess {
public function offsetSet($offset, $value): void {
var_dump(__METHOD__);
}
public function offsetExists($var): bool {
var_dump(__METHOD__);
if ($var == "foobar") {
return true;
}
return false;
}
public function offsetUnset($var): void {
var_dump(__METHOD__);
}
#[\ReturnTypeWillChange]
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)