Use the json_decode function and set the second parameter to true to convert the JSON string to PHP array; 1. The usage is $array = json_decode($jsonString, true); 2. If the second parameter is not added, the stdClass object will be returned; 3. Make sure that the input string is valid JSON, otherwise it will return null; 4. You can check for errors through json_last_error(); 5. Common errors include format problems such as unclosed quotes, redundant commas, etc.; 6. After the conversion in the example, you can access the corresponding value through the array key; as long as you pay attention to the format and parameter settings, the conversion can be completed smoothly.

When processing API data or front-end interactions, you often encounter situations where you need to convert JSON strings into PHP arrays. This operation is actually not complicated. PHP provides ready-made functions to complete this task.

Use json_decode function

The most common method in PHP is to use json_decode function. It was originally used to convert JSON strings to PHP objects, but as long as you add a parameter, you can convert it directly into an array.

usage:

 $array = json_decode($jsonString, true);

• The first parameter is your JSON string.
• Setting the second parameter to true means that the returned array is not an object.

If you don't add the second parameter, the return is a stdClass object, which may be inconvenient when processing data.

Notes:

• Make sure the entered string is indeed in valid JSON format, otherwise null will be returned.
• You can check whether there is an error by json_last_error() .
• If you are not sure if the data source is reliable, it is best to verify or filter first.

Check if JSON is valid

Sometimes the JSON string we get may be in the wrong format, so you need to verify whether it is legal first.

You can write this way:

 json_decode($jsonString);
if (json_last_error() === JSON_ERROR_NONE) {
    // is a legal JSON
} else {
    // Illegal, errors need to be handled}

Common errors include:

• Coding issues (such as Chinese characters are not escaped)
• There is an extra comma at the end
• Quotes are not closed, etc.

Example description

Suppose you have the following JSON string:

 '{"name":"John","age":30,"hobbies":["reading","coding"]}'

After using json_decode($jsonString, true) , you will get a 2D array with a clear structure and can be accessed like this:

 echo $array['name']; // Output John
echo $array['hobbies'][0]; // Output reading

Basically that's it

In general, converting JSON strings to PHP arrays only requires one function call, but in actual development, you should pay attention to format correctness and return type selection. As long as you pay attention to these small details, there will generally be no problems.

The above is the detailed content of How to convert json string to php array?. For more information, please follow other related articles on the PHP Chinese website!