标签：style io ar color os 使用 sp strong on
<?php$a = array(‘a‘=>1, ‘b‘=>0, ‘c‘=>NULL);echo ‘a test by empty: ‘ , empty($a[‘a‘]) ? ‘not exist‘ : ‘exist‘, PHP_EOL;echo ‘a test by isset: ‘ , isset($a[‘a‘]) ? ‘exist‘ : ‘not exist‘, PHP_EOL;echo ‘a test by array_key_exists: ‘ , array_key_exists(‘a‘, $a) ? ‘exist‘ : ‘not exist‘, PHP_EOL, PHP_EOL;echo ‘b test by empty: ‘ , empty($a[‘b‘]) ? ‘not exist‘ : ‘exist‘, PHP_EOL;echo ‘b test by isset: ‘ , isset($a[‘b‘]) ? ‘exist‘ : ‘not exist‘, PHP_EOL;echo ‘b test by array_key_exists: ‘ , array_key_exists(‘b‘, $a) ? ‘exist‘ : ‘not exist‘, PHP_EOL, PHP_EOL;echo ‘c test by empty: ‘ , empty($a[‘c‘]) ? ‘not exist‘ : ‘exist‘, PHP_EOL;echo ‘c test by isset: ‘ , isset($a[‘c‘]) ? ‘exist‘ : ‘not exist‘, PHP_EOL;echo ‘c test by array_key_exists: ‘ , array_key_exists(‘c‘, $a) ? ‘exist‘ : ‘not exist‘, PHP_EOL, PHP_EOL;?>
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输出结果如下：
========================================================
a test by empty: exist
a test by isset: exist
a test by array_key_exists: exist
b test by empty: not exist
b test by isset: exist
b test by array_key_exists: exist
c test by empty: not exist
c test by isset: not exist
c test by array_key_exists: exist
========================================================
注意红色高亮部分
三种方式的语法区别
所以，从准确性的角度来看，array_key_exists是最准确的！
声明：此博文是摘抄他人文章，旨在方便查找，学习使用，
PHP判断键值数组是否存在，使用empty或isset或array_key_exists
标签：style io ar color os 使用 sp strong on
原文地址：http://www.cnblogs.com/richerdyoung/p/4122844.html
