PHP implements JSON parsing and generation

PHP is a very popular server-side programming language that is widely used in the field of web development. In PHP, reading and generating JSON is a common operation because JSON is a lightweight data exchange format that can be used to store and transmit data. In this article, we will explain how to parse and generate JSON data using PHP.

1. PHP parsing JSON

1.1 Parse PHP array and convert it to JSON

In PHP, if we have an array, we can convert it to a JSON string. In the example below, we have an array that contains name, age, and gender.

<?php
$person = array(
    'name' => 'Tom',
    'age' => 30,
    'gender' => 'Male'
);

$json_string = json_encode($person);
echo $json_string;
?>

Running the above code will output the following JSON string:

{"name":"Tom","age":30,"gender":"Male"}

The json_encode() function converts the array into a JSON string. As you can see, the key name in the JSON string will be written in quotation marks, because JSON requires that the key name must be written in quotation marks.

1.2 Parse JSON string

In PHP, we can use the json_decode() function to convert a JSON string into a PHP object or array. In the example below, we have a JSON string that contains the same name, age, and gender information as above.

Running the above code will output the following PHP array:

stdClass Object
(
    [name] => Tom
    [age] => 30
    [gender] => Male
)

The json_decode() function converts a JSON string into a PHP object, and json_decode() is used without the second parameter, the stdClass object is returned by default. In the above example, we printed the PHP object and you can see that the PHP object is very similar to the original array. It is worth noting that if you need to convert to a PHP array type, you can use the second parameter of json_decode(), for example:

After running the above code, the following PHP array will be returned:

Array
(
    [name] => Tom
    [age] => 30
    [gender] => Male
)

2. PHP generates JSON

In PHP, we can use the json_encode() function to convert the PHP array Convert to a JSON string, such as:

<?php
$person = array(
    'name' => 'Tom',
    'age' => 30,
    'gender' => 'Male'
);
$json_string = json_encode($person);
echo $json_string;
?>

Output:

{"name":"Tom","age":30,"gender":"Male"}

In the above example, we convert the array $person into a JSON string and use echo to output the string.

When generating JSON, you need to pay attention to the following things:

• The key names in the array must be string types, which means integers, floating point numbers and Boolean values ​​in PHP Other types must be converted to string types in JSON;
• arrays must use UTF-8 encoding, and UTF-8 encoding is used by default in json_encode().

3. Conclusion

In this article, we introduced the basics of parsing and generating JSON in PHP. Using the json_decode() function we can convert a JSON string into a PHP object, and through the json_encode() function we can convert a PHP array into a JSON string, which makes our operations of storing and transmitting data more convenient and efficient. At the same time, we also need to pay attention to some details. For example, when generating JSON, we need to pay attention to the key name in the array must be of string type. When parsing JSON, we need to pay attention to whether the format of JSON is correct, etc.

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