Detailed explanation of json_encode() and json_decode() functions in php

Before introducing these two functions, I still want to talk about json. I don’t know how much you know about json. I feel that after I have been exposed to php for a while, I have some impressions of json, but it is just an impression. I only know that it is a data type and is relatively lightweight. But I'm really vague about its structure, and I didn't understand it until I used it now, so: Practice is a very effective way to test whether you have gained true knowledge.

1: The first is json_encode(), which means converting data to json format. So what type of data can be converted to json format?

1. Object.

Define a class, new an object, you can convert the object into json format

<?php
   class Emp {
       public $name = "";
       public $hobbies  = "";
       public $birthdate = "";
   }
   $e = new Emp();
   $e->name = "sachin";
   $e->hobbies  = "sports";
   $e->birthdate = date(&#39;m/d/Y h:i:s a&#39;, "8/5/1974 12:20:03 p");
   $e->birthdate = date(&#39;m/d/Y h:i:s a&#39;, strtotime("8/5/1974 12:20:03"));

   echo json_encode($e);
?>

Result

{"name":"sachin","hobbies":"sports","birthdate":"08\/05\/1974 12:20:03 pm"}

2. Array.

Define an array of key-value pairs

<?php
   $arr = array(&#39;a&#39; => 1, &#39;b&#39; => 2, &#39;c&#39; => 3, &#39;d&#39; => 4, &#39;e&#39; => 5);
   echo json_encode($arr);
?>

Result

{"a":1,"b":2,"c":3,"d":4,"e":5}

We can know that they are all converted to json format data. In fact, the point is not that the results are the same, because they are all converted to json? . What we need to know is that the data types that can be converted to json format are objects and arrays of key-value pairs

2: The second is json_decode(). Decode the JSON format string and convert it into a PHP variable.

First enter the code

Print the result

object(stdClass)#1 (5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

array(5) {
    ["a"] => int(1)
    ["b"] => int(2)
    ["c"] => int(3)
    ["d"] => int(4)
    ["e"] => int(5)
}

Here we can clearly see the first one The printed result is an object and the second is an array of key-value pairs.

In this way we can explain the second parameter of json_decode() well:

When it is true: it returns an array; when it is false (default is false): it returns an object.

Related recommendations:

Detailed explanation of json_encode() function in php

PHP Detailed explanation of json_encode() function and Chinese garbled code problem

PHP json_encode() function introduction

The above is the detailed content of Detailed explanation of json_encode() and json_decode() functions in php. For more information, please follow other related articles on the PHP Chinese website!