How to convert array to JSON format using json_encode function in PHP

PHP, as a server-side programming language, can easily process the transmitted data. Among them, JSON format has been widely used in data transmission. But how to convert a PHP array into a JSON formatted string? At this time, PHP's json_encode function will be used.

1. What is JSON format?

JSON (JavaScript Object Notation) is a lightweight data exchange format. Compared with XML, it is more concise and easier to read and write. The JSON format is based on JavaScript object representation and can be parsed and generated by a variety of programming languages, so it is becoming more and more popular in network transmission and data storage.

2. Use of json_encode function

The json_encode function can convert an array into a string in JSON format. This function has two parameters, the array to be converted and an optional option parameter to control the format of the output. Usage examples are as follows:

$array = array('name'=>'John', 'age'=>30, 'city'=>'New York');
echo json_encode($array);

The output of the above code is:

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

This is to use json_encode to convert a simple PHP associative array into a JSON format string.

3. Options of the json_encode function

When passing the second parameter to the json_encode function, you can control the output format. The option parameters of the json_encode function can be defined as a bit mask. The specific option parameters are as follows:

1. JSON_HEX_TAG
Replace all '<', '>', '&', ' '', '"' are converted into corresponding HTML entities. This option can be used in multiple levels of nesting.

2. JSON_HEX_AMP
only processes '&' and converts it to '&'.

3. JSON_HEX_APOS
Only processes the single quote ''' and converts it to '''.

4. JSON_HEX_QUOT
Only processes the double quote '"' and converts it to ' "'.

5, JSON_FORCE_OBJECT
"Force" the array into an object, even if the array is empty or contains only numeric keys. When this option is set, if the array only has numeric keys, it will Output an empty object.

6, JSON_UNESCAPED_SLASHES
In the URL security protocol, "/" is also considered an unsafe character, json_encode will automatically convert "/" to / format output, but If this option is set, the character will not be escaped.

Example:

$array = array('name'=>'John', 'age'=>30, 'city'=>'New York');
echo json_encode($array, JSON_HEX_TAG | JSON_HEX_APOS);

The output result is:

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

As can be seen from the above example, using The json_encode function is very simple. I believe that through the introduction of this article, readers can already master how to use the json_encode function to convert a PHP array into a JSON format string. In addition, the json_decode function can also convert a JSON format string into a PHP array , I believe that these functions will bring great convenience to everyone in practical applications.

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