What are some common mistakes to avoid when working with JSON data in PHP arrays?

One common mistake when working with JSON data in PHP arrays is not properly decoding the JSON string before trying to access its values. To avoid this, always use `json_decode()` to convert the JSON string into a PHP array before accessing its elements.

// Incorrect way - trying to access JSON data without decoding it
$jsonString = '{"name": "John", "age": 30}';
$incorrectArray = $jsonString['name']; // This will not work

// Correct way - decoding JSON string before accessing its values
$jsonString = '{"name": "John", "age": 30}';
$correctArray = json_decode($jsonString, true);
echo $correctArray['name']; // Output: John