(PHP 5 >= 5.0.0, PHP 7)
Whether an offset exists
abstract public boolean ArrayAccess::offsetExists ( mixed $offset )
Whether or not an offset exists.
This method is executed when using isset() or empty() on objects implementing ArrayAccess.
Note:
When using empty() ArrayAccess::offsetGet() will be called and checked if empty only if ArrayAccess::offsetExists() returns
TRUE.
Parameters:
offset
An offset to check for.
Returns:
Returns TRUE on success or FALSE on failure.
Note:
The return value will be casted to boolean if non-boolean was returned.
Examples:
ArrayAccess::offsetExists() example
<?php
class obj implements arrayaccess {
public function offsetSet($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"]));
?>
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)
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