SplFixedArray::offsetExists()
(PHP 5 >= 5.3.0, PHP 7)
Returns whether the requested index exists
说明
public SplFixedArray::offsetExists(int $index) : bool
Checks whether the requested index $index exists.
参数
- $index
The index being checked.
返回值
TRUE
if the requested $index exists,otherwise FALSE
It should be noted that offsetExists behaves like "offsetIsSet" rather than "offsetIsValid": <?php $arr = new SplFixedArray(3); var_dump($arr->offsetExists(1)); // false $arr[1] = 42; // $arr->offsetSet(1, 42); var_dump($arr->offsetExists(1)); // true $arr[1] = null; // $arr->offsetSet(1, null); var_dump($arr->offsetExists(1)); // true unset($arr[1]); // $arr->offsetUnset(1); var_dump($arr->offsetExists(1)); // false var_dump($arr); /* object(SplFixedArray)[1] null null null */ ?>