示例
<?php
ini_set('display_errors', 'On');
error_reporting(E_ALL);
$a = '';
echo $a['k'];
// Warning: Illegal string offset 'k'
$a = [];
echo $a['k'];
// Notice: Undefined index: k
总结
- 尝试把字符串当成数组取元素时,会报错:Warning: Illegal string offset
- 尝试读取数组不存在的元素时,会报错:Notice: Undefined index: k