Using JSON in PHP: json_encode and json_decode Explained with Examples

JSON is a lightweight data-interchange format widely used in network communication, supported by almost all programming languages.

The article outlines the basic syntax rules of JSON: key‑value pairs, comma separation, curly braces for objects, and square brackets for arrays.

In PHP, the json_encode() function converts arrays to JSON strings. Example code demonstrates encoding a sequential array, a non‑sequential array, the effect of unsetting an element, and encoding a two‑dimensional array:

<?php
echo "连续数组";
$sequential = array（"foo"，"bar"，"baz"，"blong"）;
echo json_encode（$sequential）;
echo "<br/>非连续数组";
$nonsequential = array（1=>"foo"，2=>"bar"，3=>"baz"，4=>"blong"）;
echo json_encode（$nonsequential）;
echo "<br/>删除一个连续数组值的方式产生的非连续数组";
unset（$sequential[1]）;
echo json_encode（$sequential）;
echo "<br/>二维数组";
$arr = array（array（'name'=>'chenxiaolong'），array（'name'=>'zhangsan'））;
echo json_encode（$arr）;
?>

When encoding a two‑dimensional array, the outermost JSON structure is an array (enclosed in square brackets) containing the JSON representations of each inner array.

The json_decode() function parses JSON strings back into PHP variables. By default it returns an object; passing true as the second argument returns an associative array. Example code shows decoding a JSON string to an object and to an array:

<?php
$json = '{"a"：1，"b"：2，"c"：3，"d"：4，"e"：5}';
var_dump（json_decode（$json））;
echo "<br/>";
var_dump（json_decode（$json，true））;
?>

The article concludes that setting the second parameter of json_decode() to true converts JSON data into an array.