Question

In PHP, I noticed that if I have an array and then json_encode() it, the boolean values get converted to true and false. However, I want them to be converted to 1 and 0, respectively.

Here’s an example:

$data = Array("foo" => true, "bar" => false, "baz" => false, "biz" => true);
print json_encode($data);

The above outputs:

{"foo":true,"bar":false,"baz":false,"biz":true}

However, if true and false were 1 and 0 instead, we could have a shorter string, which would take less time to transfer over the Internet:

{"foo":1,"bar":0,"baz":0,"biz":1}

How can I make PHP encode JSON using 1 and 0 instead of true and false?

Answer 1

I figured it out. You can use the array_walk or array_walk_recursive function in PHP to cast the booleans to integers before encoding the JSON. I wrote a function to do that:

function change_booleans_to_numbers(Array $data){
    // Note the order of arguments and the & in front of $value 
    function converter(&$value, $key){
        if(is_bool($value)){
            $value = ($value ? 1 : 0);
        }
    }
    array_walk_recursive($data, 'converter');
    return $data;
}

Here’s a demonstration script:

<?php
// Make the browser display this as plain text instead of HTML 
header("Content-Type:text/plain");

function change_booleans_to_numbers(Array $data){
    function converter(&$value, $key){
        if(is_bool($value)){
            $value = ($value ? 1 : 0);
        }
    }
    array_walk_recursive($data, 'converter');
    return $data;
}

$data = Array("foo" => true, "bar" => false, "baz" => false, "biz" => true);

print "Original:" . PHP_EOL;
var_dump($data);
print json_encode($data) . PHP_EOL;
print PHP_EOL;

$changed = change_booleans_to_numbers($data);
print "Processed:" . PHP_EOL;
var_dump($changed);
print json_encode($changed) . PHP_EOL;

The script outputs:

Original:
array(4) {
  ["foo"]=>
  bool(true)
  ["bar"]=>
  bool(false)
  ["baz"]=>
  bool(false)
  ["biz"]=>
  bool(true)
}
{"foo":true,"bar":false,"baz":false,"biz":true}

Processed:
array(4) {
  ["foo"]=>
  int(1)
  ["bar"]=>
  int(0)
  ["baz"]=>
  int(0)
  ["biz"]=>
  int(1)
}
{"foo":1,"bar":0,"baz":0,"biz":1}