array2json() - Convert PHP arrays to JSON

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array2json is a PHP function that will convert the array given as its argument into a JSON string. The created JSON string will be returned. This is very useful in Ajax apps using JSON over XML. If you are using XML, you better off using my xml2array() JavaScript function.

Note: This is an old function - if you use a new version of PHP(5.2 or newer) you will get the json_encode() function. That can be used to convert arrays to a JSON string.

Usage

First you need a PHP array. For example...

$data = array(
    'success'    =>    "Sweet",
    'failure'    =>    false,
    'array'      =>    array(),
    'numbers'    =>    array(1,2,3),
    'info'       =>    array(
                        'name'    =>    'Binny',
                        'site'    =>    'http://www.openjs.com/'
                 )
);

Provide this array as the argument of the array2json() function...

$json = array2json($data);

The resulting string will be(actual output - the source says print array2json($data);)...


{"success":"Sweet","failure":false,"empty_array":[],"numbers":[1,2,3],"info":{"name":"Binny","site":"http:\/\/www.openjs.com\/"}}

I am formatting the output for better readability...

{
	"success":"Sweet",
	"failure":false,
	"empty_array":{},
	"numbers":[1,2,3],
	"info":{
		"name":"Binny",
		"site":"http://www.openjs.com/"
	}
}

Handled Data types

All the basic data types are handled...

Objects are not handled.

Code

<?php
function array2json($arr) {
    if(function_exists('json_encode')) return json_encode($arr); //Lastest versions of PHP already has this functionality.
    $parts = array();
    $is_list = false;

    //Find out if the given array is a numerical array
    $keys = array_keys($arr);
    $max_length = count($arr)-1;
    if(($keys[0] == 0) and ($keys[$max_length] == $max_length)) {//See if the first key is 0 and last key is length - 1
        $is_list = true;
        for($i=0; $i<count($keys); $i++) { //See if each key correspondes to its position
            if($i != $keys[$i]) { //A key fails at position check.
                $is_list = false; //It is an associative array.
                break;
            }
        }
    }

    foreach($arr as $key=>$value) {
        if(is_array($value)) { //Custom handling for arrays
            if($is_list) $parts[] = array2json($value); /* :RECURSION: */
            else $parts[] = '"' . $key . '":' . array2json($value); /* :RECURSION: */
        } else {
            $str = '';
            if(!$is_list) $str = '"' . $key . '":';

            //Custom handling for multiple data types
            if(is_numeric($value)) $str .= $value; //Numbers
            elseif($value === false) $str .= 'false'; //The booleans
            elseif($value === true) $str .= 'true';
            else $str .= '"' . addslashes($value) . '"'; //All other things
            // :TODO: Is there any more datatype we should be in the lookout for? (Object?)

            $parts[] = $str;
        }
    }
    $json = implode(',',$parts);
    
    if($is_list) return '[' . $json . ']';//Return numerical JSON
    return '{' . $json . '}';//Return associative JSON
}
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