How does PHP handle non-existent constants when accessing values in arrays?

When accessing values in arrays in PHP, if a constant that does not exist is used as a key, PHP will automatically convert it to a string. This can lead to unexpected behavior if the constant name is mistyped or does not exist. To avoid this issue, it is recommended to always define constants before using them as keys in arrays. 

define('KEY', 'value');

$array = [
    KEY => 'This is the value for KEY'
];

echo $array[KEY]; // Output: This is the value for KEY

Keywords

PHP constants arrays error handling undefined constant

Related Questions