json_encode retain float values as is it is

Question

I need to convert an array to json and want to retain the precision as well as type of the data.

   $a = array("num" => 10000.00);
   print_r(json_encode($a));

In the above example 10000.00 is being converted to 10000. How can I retain everything in the json.

Answer 1

The best you can do in php 5.6+, is to make sure it is encoded as a float. However, that does not keep the precision:

<?php
$a = array("num" => 10000.00);
print_r(json_encode($a, JSON_PRESERVE_ZERO_FRACTION));

If datatype and precision are important, you would need to send an additional parameter, for example:

$a = ["num" => [
        "value" => 10000.0, 
        "precision" => 2
    ]
];
print_r(json_encode($a, JSON_PRESERVE_ZERO_FRACTION));

If you always want the precision of 2 digits (like monetary values), you should multiply the values by 100 and store these as integers to avoid rounding problems. Also see PHP - Floating Number Precision.