Question

I have php code that returns this from a database,

[
{
    "Time": "2012-11-27 16:10:35",
    "NumPlayers": "1"
},
{
    "Time": "2012-11-27 16:24:55",
    "NumPlayers": "1"
},
{
    "Time": "2012-11-27 16:25:37",
    "NumPlayers": "2"
},
{
    "Time": "2012-11-27 16:29:33",
    "NumPlayers": "2"

The times are MySQL timestamps. I need to get it into this format to use with Highcharts javascript charting.

data: [
[Date.UTC(1970,  9,  9), 0   ],
[Date.UTC(1970,  9, 14), 0.15],
[Date.UTC(1970, 10, 28), 0.35],
[Date.UTC(1970, 11, 12), 0.46],

I’m having trouble figuring out how to loop through the MySQL results and convert the timestamps to javascript Date.UTC objects. I need to place the NumPlayers value after the Date.UTC objects, and output it in the format below. I’m a PHP and javascript noob :\

It should look something like this:

data: [
[Date.UTC(2012, 11, 27, 16, 10, 35), 1],
[Date.UTC(2012, 11, 27, 16, 24, 55), 1],
[Date.UTC(2012, 11, 27, 16, 25, 37), 2],
[Date.UTC(2012, 11, 27, 16, 29, 33), 2],

Answer 1

You should realize that Date.UTC(2012, 11, 27, 16, 10, 35) simply returns the number of milliseconds since the epoch (1356624635000). Therefore, you can just convert your object into UNIX timestamps (times a 1000 since JS works with millisecond timestamps, but PHP works with seconds).

Sample Code

$data = '[{"Time": "2012-11-27 16:10:35", "NumPlayers": "1"}, {"Time": "2012-11-27 16:24:55", "NumPlayers": "1"}]';

// Make sure date is parsed as UTC
date_default_timezone_set("UTC");

// Convert items into the desired format
$mapper = function($item) {
    return array(strtotime($item->Time)*1000, $item->NumPlayers);
}

echo json_encode(array_map($mapper, json_decode($data)));

Output

[[1354032635000,"1"],[1354033495000,"1"]]