php判断数组中是否存在指定键(key)的方法

时间:2021-01-05 10:03:12

本文实例讲述了php判断数组中是否存在指定键(key)的方法。分享给大家供大家参考。具体分析如下:

php中有两个函数用来判断数组中是否包含指定的键,分别是array_key_exists和isset

array_key_exists语法如下

array_key_exists($key, $array)

如果键存在返回true isset函数语法如下

isset($array[$key])

如果键存在返回true

演示代码如下:

<?php
$array = array ( "Zero" => "PHP" , "One" => "Perl" , "Two" => "Java" );
print ( "Is 'One' defined? " . array_key_exists ( "One" , $array ). "\n" );
print ( "Is '1' defined? " . array_key_exists ( "1" , $array ). "\n" );
print ( "Is 'Two' defined? " .isset( $array [ "Two" ]). "\n" );
print ( "Is '2' defined? " .isset( $array [2]). "\n" );
?>
返回结果如下:
Is 'One' defined? 1
Is '1′ defined?
Is 'Two' defined? 1
Is '2′ defined?