How to convert json string to array object in php

PHP is a very popular server-side programming language. It has powerful string processing functions and supports converting JSON-formatted strings into arrays or objects. In this article, we will introduce how to convert JSON string to array object in PHP.

1. The concept of JSON

The full name of JSON is JavaScript Object Notation, which is translated as "JavaScript Object Notation". It is a lightweight data exchange format that is widely used in Web transmission and data storage. Data in JSON format can be saved in the form of a string, or can be represented directly in JavaScript as an object or array.

2. JSON functions in PHP

PHP provides a series of JSON functions for conversion between strings in JSON format and data types in PHP. The following are some commonly used JSON functions:

1. json_encode(): Convert the data type in PHP to JSON format;
2. json_decode(): Convert the string in JSON format to Data type in PHP;
3. json_last_error(): Get the error caused by JSON.

3. Convert JSON string to array

Converting JSON string to array is relatively simple, just use the json_decode() function in PHP. For example, the following code converts a JSON-formatted string into a PHP array:

$json_str = '{"name":"Tom","age":20,"sex":"male"}';
$arr = json_decode($json_str, true);
print_r($arr);

In the above code, we first define a JSON-formatted string $json_str, which represents a male named Tom , aged 20 years. We then use the json_decode() function to convert this string to an array in PHP and assign it to the variable $arr. Finally, we use the print_r() function to print the array and get the following result:

Array
(

[name] => Tom
[age] => 20
[sex] => male

)

As can be seen from the result, the JSON character The string was successfully converted to a PHP array.

4. Convert JSON string to object

In addition to converting JSON string to array, we can also convert it to object in PHP. In order to achieve this, we need to omit the second parameter or set it to false when calling the json_decode() function. For example, the following code converts a JSON-formatted string into a PHP object:

$json_str = '{"name":"Tom","age":20,"sex":"male"}';
$obj = json_decode($json_str);
var_dump($obj);

In the above code, we define a JSON-formatted string $json_str and use the json_decode() function to convert it is an object in PHP. Finally, we use the var_dump() function to display the object and get the following results:

object(stdClass)#1 (3) {
["name"]=>
string(3) "Tom"
["age"]=>
int(20)
["sex"]=>
string(4) "male"
}

It can be seen from the results that the JSON string was successfully converted into a PHP object.

5. Convert arrays or objects to JSON strings

In addition to converting JSON strings to arrays or objects in PHP, we can also convert arrays or objects in PHP A string in JSON format. To achieve this, we need to use the json_encode() function in PHP. For example, the following code converts a PHP array into a string in JSON format:

$arr = array('name' => 'Tom', 'age' => 20, 'sex' => 'male');
$json_str = json_encode($arr);
echo $json_str;

In the above code, we define a PHP array $arr, which represents a male named Tom, age 20 . We then use the json_encode() function to convert the array into a JSON-formatted string and assign it to the variable $json_str. Finally, we use the echo statement to print the string and get the following results:

{"name":"Tom","age":20,"sex":"male"}

As can be seen from the results, the PHP array was successfully converted into a JSON format string.

6. Convert array objects to JSON strings

In some cases, we need to convert array objects in PHP into JSON format strings. To achieve this, we can first convert the array object to an object and then convert it to a JSON-formatted string using the json_encode() function. For example, the following code converts an array object into a string in JSON format:

$arr = array(
    array('name' => 'Tom', 'age' => 20, 'sex' => 'male'),
    array('name' => 'Lucy', 'age' => 18, 'sex' => 'female')
);
$obj = (object)$arr;
$json_str = json_encode($obj);
echo $json_str;

In the above code, we define a PHP array $arr containing two array objects. Then, we use (object)$arr to convert it into a PHP object $obj, then use the json_encode() function to convert the object into a JSON-formatted string and assign it to the variable $json_str. Finally, we use the echo statement to print the string and get the following results:

[{"name":"Tom","age":20,"sex":"male"},{"name" :"Lucy","age":18,"sex":"female"}]

It can be seen from the results that the PHP array object was successfully converted into a JSON format string.

To sum up, through the above examples, we can clearly understand how to convert JSON string to array or object, and convert array or object to JSON string in PHP. These operations are very common in our PHP programming process, and mastering them will greatly improve our programming efficiency.

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