SplFixedArray::offsetExists

(PHP 5 >= 5.3.0, PHP 7)

SplFixedArray::offsetExists — Returns whether the requested index exists

说明

public bool SplFixedArray::offsetExists ( int $index )

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

User Contributed Notes

depoemarc at swap dot fn dot ln dot googlemail dot com 25-Jun-2015 11:47
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
*/
?>