<?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;
?>
|
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
- empty： 参数为0或为NULL时（如上面列子），empty均返回TRUE，
- isset： 参数为NULL时，返回FALSE，0与NULL在PHP中是有区别的，isset(0)返回TRUE
- array_key_exists： 纯粹的判断数组键值对是否存在，无论值是多少
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，