How to convert json to array in php

PHP is a very popular server-side programming language that can handle various types of data and provides a rich function library to process data. JSON (JavaScript Object Notation) is a lightweight data exchange format that is widely used in front-end and back-end data interaction, API interface data transmission and other fields. In PHP, converting a JSON string into an array is a common operation. So, how does PHP convert JSON into an array? This article will explain it to you in detail.

In PHP, converting JSON into an array mainly relies on two core functions, namely json_encode and json_decode. Among them, the json_encode function converts a PHP array or object into a JSON format string, and the json_decode function converts a JSON format string into a PHP array or object. The specific usage of these two functions is introduced below.

1. json_encode function

json_encode function is used to convert PHP arrays or objects into JSON format strings. The basic syntax of the function is as follows:

string json_encode ( mixed $value , int $options = 0 , int $depth = 512 )

where , the parameter $value is required and represents the PHP array or object to be encoded. The $options parameter represents encoding options, and optional values ​​are defined in the form of constants. For example, JSON_PRETTY_PRINT means formatting a JSON format string, JSON_UNESCAPED_UNICODE means not escaping non-ASCII characters, etc. The $depth parameter indicates the maximum recursion depth, and the default value is 512.

The following is a simple example to convert a PHP array into a JSON format string:

<?php $arr = array(&#39;name&#39; => '张三', 'age' => 18);
$json = json_encode($arr);
echo $json; //输出{"name":"张三","age":18}
?>

2. json_decode function

json_decode function is used to convert The JSON format string is converted into a PHP array or object. The basic syntax of the function is as follows:

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

Among them, the parameter $json is required and represents the JSON format string to be decoded. The $assoc parameter indicates whether the returned result is an associative array. The optional value is true or false. The default is false, which means the returned result is an object. The $depth parameter indicates the maximum recursion depth, and the default value is 512. The $options parameter represents decoding options, and optional values ​​are defined in the form of constants. For example, JSON_BIGINT_AS_STRING represents processing integers greater than PHP_INT_MAX as strings, JSON_OBJECT_AS_ARRAY represents decoding JSON format strings into associative arrays, etc.

The following is a simple example to convert a JSON format string into a PHP array:

<?php $json = &#39;{"name":"张三","age":18}&#39;;
$arr = json_decode($json, true);
print_r($arr); //输出Array ( [name] => 张三 [age] => 18 )
?>

It should be noted that when using the json_decode function to decode a JSON format string, if the JSON format There are Chinese characters in the string, and the parameter $assoc needs to be set to true to ensure that the decoded result is an associative array rather than an object.

Summary

This article introduces how PHP converts JSON format strings into arrays, mainly relying on the two core functions of json_encode and json_decode. By using these two functions, you can easily convert PHP arrays or objects into JSON format strings, and convert JSON format strings into PHP arrays or objects. It should be noted that when encoding and decoding JSON, the encoding and decoding options must be used reasonably to ensure the accuracy and efficiency of encoding and decoding.

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