Why is it important to use associative array indexes with quotes in PHP?

Using associative array indexes with quotes in PHP is important because it ensures that the index is treated as a string. If quotes are not used, PHP will treat the index as a constant if it is not defined, which can lead to unexpected behavior or errors. By using quotes, you explicitly define the index as a string, preventing any potential issues. 

// Incorrect way of accessing an associative array index without quotes
$array = ['key' => 'value'];
echo $array[key]; // This will throw a notice about an undefined constant 'key'

// Correct way of accessing an associative array index with quotes
$array = ['key' => 'value'];
echo $array['key']; // This will output 'value' without any errors

Keywords

associative arrays indexes quotes PHP syntax

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