How to convert JSON data to array in PHP

During the development process, we often encounter the need to convert data in JSON format into PHP arrays. This need is very common when interacting with the front end, receiving data from other system interfaces, etc. This article will introduce how to convert JSON data to PHP array in PHP.

1. PHP built-in function json_decode()

PHP has a built-in function json_decode(), which can convert a JSON format string into a PHP array. The following is an example of using the json_decode() function:

$json = '{"name":"john","age":30,"city":"New York"}';
$array = json_decode($json, true);

print_r($array);

The output result is:

Array
(
    [name] => john
    [age] => 30
    [city] => New York
)

In the above example, $json is a string in JSON format, and $array is using json_decode( ) function converts $json into a PHP array. It should be noted that the second parameter of the json_decode() function must be true, which means converting the converted JSON object into a PHP array.

2. Parsing JSON containing Chinese

When processing JSON data containing Chinese, we need to pay attention to the problem of character encoding, otherwise we may encounter errors during the conversion process .

Suppose there is a JSON string containing Chinese, as shown below:

$json = '{"name":"张三","age":30}';

When the above code is used to convert the JSON string into a PHP array, a Notice error will be generated, prompting "json_decode(): Input string contains invalid UTF-8 characters" (JSON string contains invalid UTF-8 characters).

This is because the json_decode() function only supports UTF-8 encoding by default, and the Chinese characters in the JSON string are encoded in GBK or other encoding methods, so we need to convert them to UTF- 8 encoding, and then JSON conversion.

Use the PHP built-in function iconv() to convert the string from GBK to UTF-8 encoding:

$json = '{"name":"张三","age":30}';
$json_utf8 = iconv('GBK', 'UTF-8//IGNORE', $json);

$array = json_decode($json_utf8, true);

print_r($array);

The result output is:

Array
(
    [name] => 张三
    [age] => 30
)

3. JSON data Verification

When converting JSON data, sometimes we need to verify it to ensure that it conforms to our expected structure and format.

PHP has a built-in function json_last_error() that can obtain the error code generated by the last JSON conversion operation. We can judge whether the JSON data meets expectations based on the error code.

For example, the following code demonstrates how to determine whether an illegal JSON string is as expected when converting it:

$json = '{"name":"john","age":30,},
    {"name":"mike","age":32}';
$array = json_decode($json, true);

if (json_last_error() === JSON_ERROR_NONE) {
    echo 'JSON 格式正确';
} else {
    echo 'JSON 格式错误';
}

In the above code, $json contains two JSON Objects, not separated by commas, are JSON format errors. Therefore, the json_last_error() function returns JSON_ERROR_SYNTAX, indicating a JSON syntax error.

4. Readability of JSON data

When processing JSON data, in order to facilitate debugging and reading, we can also add indentation and line breaks to the JSON data. Make it easier to read.

PHP’s built-in function json_encode() can convert a PHP array into a more readable JSON format string. For example:

$array = [
    'name' => 'john',
    'age' => 30,
    'city' => 'New York'
];

$json = json_encode($array, JSON_PRETTY_PRINT);

echo $json;

The output result is:

{
    "name": "john",
    "age": 30,
    "city": "New York"
}

In the above code, after we convert $array into a string in JSON format, we pass a JSON_PRETTY_PRINT parameter, which means that the JSON string will be Indentation and line breaks are handled to improve its readability.

It should be noted that the parameter JSON_PRETTY_PRINT in the json_encode() function is only supported in PHP version 5.4 and above.

Summary

In PHP, we can use the built-in function json_decode() to convert a JSON-formatted string into a PHP array. When processing JSON data containing Chinese, you need to pay attention to character encoding issues; when converting JSON data, you need to verify whether it meets expectations; when generating JSON data, you can use the json_encode() function to optimize its readability.

The above is the method of converting JSON to PHP array. I hope it will be helpful to you in actual development.

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