How to convert json string to array and object in php

In the PHP development process, converting Json strings into objects and arrays is a common operation. Json is a data format, while PHP is a programming language, which can convert Json strings into PHP objects and arrays through the json_decode() function. In this article, we will learn how to convert Json strings to PHP associative arrays and objects using one of the most common methods of using Json strings.

Format of Json string

Before we learn to convert Json string into PHP objects and arrays, let us first review the format of Json string. Json string is a text data that stores data in the form of key-value pairs. Each key-value pair consists of a "key" and a "value". The "key" is surrounded by double quotes. The "value" can be a numerical value, a string, a Boolean value, a null value, a Json object or a Json array.

The following is an example of a Json string:

{
    "name": "张三",
    "age": 25,
    "gender": "男",
    "address": {
        "province": "北京",
        "city": "朝阳区",
        "street": "和平路"
    },
    "hobbies": [
        "篮球",
        "游泳",
        "旅游"
    ]
}

In the above example, "name", "age", "gender", "address" and "hobbies" are the Json The "keys" of the string correspond to "Zhang San", "25", "male", "address" and "hobbies" respectively. Among them, "address" is a Json object, and "hobbies" is a Json array.

Convert Json string to PHP array

In PHP, the way to convert Json string to array is to use the json_decode() function. The syntax of the json_decode() function is as follows:

mixed json_decode ( string $json [, bool $assoc = false [, int $depth = 512 [, int $options = 0 ]]] )

Among them, the $json parameter is the Json string to be converted, and the $assoc parameter indicates whether to convert the Json object into a PHP associative array (true indicates conversion into a PHP associative array, false indicates conversion to a PHP object), the $depth parameter indicates the maximum depth of conversion (default is 512), and the $options parameter indicates options during decoding (default is 0).

The following is an example of converting a Json string into a PHP array:

  <?php   $json_str = &#39;{"name":"张三","age":25,"gender":"男","address":{"province":"北京","city":"朝阳区","street":"和平路"},"hobbies":["篮球","游泳","旅游"]}&#39;;

  $arr = json_decode($json_str, true);

  print_r($arr);

  ?>

In the above example, we first define a Json string $json_str. We use the json_decode() function to convert $json_str to a PHP array and store the result in the $arr variable. Finally, we use the print_r() function to output the contents of the array.

The output result is as follows:

Array
(
    [name] => 张三
    [age] => 25
    [gender] => 男
    [address] => Array
        (
            [province] => 北京
            [city] => 朝阳区
            [street] => 和平路
        )

    [hobbies] => Array
        (
            [0] => 篮球
            [1] => 游泳
            [2] => 旅游
        )

)

Convert Json string to PHP object

In addition to converting Json string to PHP array, This can be converted to a PHP object. This process can also be implemented using the json_decode() function, just set the second parameter to false or omit it.

The following is an example of converting a Json string to a PHP object:

  <?php   $json_str = &#39;{"name":"张三","age":25,"gender":"男","address":{"province":"北京","city":"朝阳区","street":"和平路"},"hobbies":["篮球","游泳","旅游"]}&#39;;

  $obj = json_decode($json_str);

  print_r($obj);

  ?>

In the above example, we set the second parameter to false, and the result will be converted to a PHP object.

The output result is as follows:

stdClass Object
(
    [name] => 张三
    [age] => 25
    [gender] => 男
    [address] => stdClass Object
        (
            [province] => 北京
            [city] => 朝阳区
            [street] => 和平路
        )

    [hobbies] => Array
        (
            [0] => 篮球
            [1] => 游泳
            [2] => 旅游
        )

)

Convert the object in the Json string to a PHP array

If the Json string contains an object, And you need to convert it to a PHP associative array, you can first convert it to a PHP object, and then use the typecast() function to convert it to an associative array.

The following is an example of converting an object in a Json string to a PHP associative array:

  <?php   $json_str = &#39;{"name":"张三","age":25,"gender":"男","address":{"province":"北京","city":"朝阳区","street":"和平路"},"hobbies":["篮球","游泳","旅游"]}&#39;;

  $obj = json_decode($json_str);

  $arr = json_decode(json_encode($obj), true);

  print_r($arr);

  ?>

In the above example, we first use the json_decode() function to convert the Json string to PHP object. Then use the json_encode() function to convert the PHP object to a Json string and again use the json_decode() function to convert it to a PHP associative array. Finally, we use the print_r() function to output the contents of the array.

The output is the same as the first example.

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