How would I convert this array to usable javascript array?

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],

you can parse your data and after build an simple array.. I cannot understand what you really want.. — thiagoh
– thiagoh, Commented Dec 4, 2012 at 17:55
@GerardWesterhof It's usually better to do parsing on the server if you can get away with it, and in this case, the OP can. — Ruan Mendes
– Ruan Mendes, Commented Dec 4, 2012 at 19:10
Probably the best solution is parse on the backend, like @JuanMendes mentioned. — Ricardo Lohmann
– Ricardo Lohmann, Commented Dec 4, 2012 at 20:08
@RicardoLohmann But don't do the parsing on your own as some have suggested — Ruan Mendes
– Ruan Mendes, Commented Dec 4, 2012 at 21:33

Ruan Mendes · Accepted Answer · 2012-12-04 19:54:04Z

2

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"]]

edited Dec 4, 2012 at 19:54

answered Dec 4, 2012 at 19:05

Ruan Mendes

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Comments

Havelock · Accepted Answer · 2012-12-04 18:24:39Z

1

You seem to be getting straight JSON from your database, which you can always convert into an array:

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

After which you can simply iterate through the array and print out the contents of the array in the JS format you need. Something like that:

echo 'data: [' . PHP_EOL;
foreach ($arrayData as $item) {
    echo '[Date.UTC(';
    $tmp = preg_split( '/(-| |\:)/', $item['Time'] );
    echo implode(', ', $tmp);
    echo '), ' . $item['NumPlayers'] . '],';
    echo PHP_EOL;
}
echo PHP_EOL . '];';

edited Dec 4, 2012 at 18:24

answered Dec 4, 2012 at 17:56

Havelock

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5 Comments

Ruan Mendes Over a year ago

The question is specifically about making them dates, json_decode isn't going to do that. You have to do it on the client since JSON doesn't support dates

Havelock Over a year ago

@JuanMendes the output is the same as the OP wanted it codepad.org/DTlp0pr2

Ruan Mendes Over a year ago

Now that you added extra code to generate the JSON (which is not valid JSON) on your own, yes it will

Ruan Mendes Over a year ago

The second chunk of code, which takes the result of json_decode and makes an almost JSON string out of it, that was added after my initial comments

Ruan Mendes Over a year ago

I just submitted an answer that doesn't involve generating pseudo-JSON on your own. It sends properly formatted JSON over the wire (that is because Date.UTC just returns a number)

Sean Vieira · Accepted Answer · 2012-12-04 19:55:41Z

1

You can split the time string into sections using /[^\d]+/g:

var finalData = [], numbers=/[^\d]+/g, item, dateParts, newDate;
for (var i=0, l=data.length; i<l; i++) {
     item = data[i];
     dateParts = item.Time.split(numbers);
     newDate = Date.UTC.apply(Date, dateParts);
     finalData.push([newDate, item.NumPlayers]);
}

See also: MDN's documentation on JavaScript regular expressions (/[^\d]/g is a regex).

edited Dec 4, 2012 at 19:55

answered Dec 4, 2012 at 18:00

Sean Vieira

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5 Comments

Ruan Mendes Over a year ago

I prefer this approach of doing it on the client, so that proper JSON is sent over the wire, not JS as [Date.UTC(2012, 11, 27, 16, 10, 35), 1],. My only recommendation would be to have the server send a timestamp so the client doesn't need to parse the time

Ruan Mendes Over a year ago

Except that you're splitting on the wrong thing, you need to split on the separators, not on the numbers. Also, your call to Date.apply is incorrect, it should be calling the UTC method. Notice your code is giving the wrong timestamps.jsfiddle.net/ck9bL But this one jsfiddle.net/ck9bL/3/works well. You should update the answer accordingly.

Ruan Mendes Over a year ago

I provided a server side answer that doesn't require parsing on the server side and doesn't require generating JSON on your won.

Sean Vieira Over a year ago

@JuanMendes - Chuckles, yep, that's the exact opposite of what I wanted - I've updated my answer. Thanks for the catch!

Ruan Mendes Over a year ago

You should try your code... It still doesn't work, look at jsfiddle.net/ck9bL/3 for working code

Ricardo Lohmann · Accepted Answer · 2012-12-04 23:42:15Z

1

The best way to provide data to Highcharts is getting data formated from database, so that you don't have to do it on client side.

To do it you just have to change your query to something like the following.

Backend
$query = "SELECT UNIX_TIMESTAMP(date) * 1000 AS 'date', value FROM ...";

Then to send the result to frontend:
echo json_encode($result);

Frontend
To get the result on frontend, this case using jQuery and assuming that url is your url:

$.getJSON(url, function(json) {
    // decode json
    var data = $.parseJSON(json);
    // Then you just have to pass it to your series
});

Or better, store date values in UTC.

answered Dec 4, 2012 at 23:42

Ricardo Lohmann

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1 Comment

Ruan Mendes Over a year ago

If the OP can do this, even better, no need to parse time strings

kossoy · Accepted Answer · 2012-12-04 18:09:42Z

0

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

    var length = php_data.length;
    hc_data = [];

    for(var i = 0; i< length; i++){
      php_date = new Date(php_data[i]["Time"]);
      hc_data.push(
        [
            Date.UTC(
                php_date.getFullYear(), 
                php_date.getMonth() + 1, 
                php_date.getDate()
            ),
            php_data[i]["NumPlayers"]
        ]
      );
    }

    // hc_data is your Array

answered Dec 4, 2012 at 18:09

kossoy

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