Averaging Times Using Javascript

I am building an app using Phonegap and JQuery. The app stores ( using window.localStorage ) a set of times (no more than 10) in the format. HH:MM:SS.mm There are a number of

Solution 1:

var times= [ '00:00:03.00', '00:00:05.00', '00:00:02.00', '00:00:06.00'],
    date = 0,
    result = '';
function offsetify(t){
    return t < 10 ? '0' + t : t;
}
for(var x = 0; x < times.length; x++ ) {
    var tarr = times[x].split(':');
    date += new Date(0, 0, 0, tarr[0], tarr[1], tarr[2].split('.')[0], tarr[2].split('.')[1]).getTime();   
}
var avg = new Date(date/times.length);
result = offsetify(avg.getHours()) + ':' + offsetify(avg.getMinutes()) + ':' + offsetify(avg.getSeconds()) + '.' + offsetify(avg.getMilliseconds());

DEMO

Solution 2:

if you are going to also have millisecond values and you want to consider them, then convert the times into millisecond. Now, add them and divide them by the number of records. Else, convert everything to seconds and find the average - you get the answer in seconds, of course.

The conversion is quite simple if take little time to think over it. Here's how to convert.

To milliseconds:

functionconvertToMS(timeStr) {      // timeStr in format 'HH:MM:SS.mm'var I = parseInt;  // for brevityvar t = timeStr,
        h = I( t.substr(0,2) ),
        m = I( t.substr(3,2) ),
        s = I( t.substr(6,2) ),
        ms = I( t.substr(9,2) );

    return h * 3600000 + m * 60000 + s * 1000 + ms;
}

To seconds:

functionconvertToS(timeStr) {      // timeStr in format 'HH:MM:SS[.mm]'  -- .mm is ignored.var I = parseInt;  // for brevityvar t = timeStr,
        h = I( t.substr(0,2) ),
        m = I( t.substr(3,2) ),
        s = I( t.substr(6,2) );

    return h * 3600 + m * 60 + s;
}

After the conversion's done, add them up and find the average.

UPDATE: To convert back to the format 'HH:MM:SS.mm', we change back the time into 'chunks' of hours, minutes, seconds and (if applicable) milliseconds.

functionchunkifyFromSec(time) {  // time in svar t = "",
        h = Math.floor(time / 3600),
        m = Math.floor( (t - (h * 3600)) / 60 ),
        s = t - (h * 3600) - (m * 60);
    return {
        HH: h, MM: m, SS: s, mm: 0
    };
}
functionchunkifyFromMS(time) {   // time in msvar t = "",
        h = Math.floor(time / 3600000),
        m = Math.floor( (t - (h * 3600000)) / 60000 ),
        s = Math.floor( (t - (h * 3600000) - (m * 60000)) / 1000 ),
        mm = t - (h * 3600000) - (m * 600000) - (s * 1000);
    return {
        HH: h, MM: m, SS: s, mm: mm
    };
}

Then, we return the string in the format 'HH:MM:SS.mm' using this:

functiontoTimeStr(chunks) {
    return
           (chunks.HH < 0 ? '0' : '') + chunks.HH + ":"
           += (chunks.MM < 0 ? '0' : '') + chunks.MM + ":"
           += (chunks.SS < 0 ? '0' : '') + chunks.SS + "."
           += (chunks.mm < 0 ? '0' : '') + chunks.mm
}

Solution 3:

I don't have much experience with Javascript so I might have some syntax errors but I think you could do something like

var i = 0;
var totalTime = 0.0;
for (i=0; i < scores.length; i++) {
    var hours = parseFloat(scores[i].substring(0, 2)); //get numeric value for hoursvar minutes = parseFloat(scores[i].substring(3,5)); //get numeric value for minutesvar seconds = parseFloat(scores[i].substring(6)); //get numeric for the secondsvar time = ((hours * 60) + minutes) * 60 + seconds; //60 minutes in an hour, 60 seconds in a minute
    totalTime += time;
}

var avgTime = totalTime/scores.length;

var avgHours = Math.floor(avgTime / 3600); //60*60var avgHoursStr = String(avgHours);

var avgMinutes = Math.floor((avgTime % 3600) / 60); //mod to get rid of the hoursvar avgMinutesStr = String(avgMinutes);

var avgSeconds = avgTime - avgHours*3600 - avgMinutes*60; //get the remainder. Can't use mod due to decimalvar avgSeconds = String(avgSeconds);

//Concat strings. Add the ":" spacers. Where necessary, add leading 0var avgStr = (avgHoursStr.length > 1 ? "" : "0") + avgHoursStr + ":" + (avgMinutesStr.length > 1 ? "" : "0") + avgMinuteStr + ":" + avgSecondsStr;

[EDIT - Thanks to Parth Thakkar for point out my problem]

Solution 4:

To return the answer in milliseconds or seconds:

var times = ["00:00:03.00", "00:00:05.00", "00:00:02.00", "00:00:06.00"];

function averageTimes(times,unit) {
    if (!times) {
        returnfalse;
    }
    else {
        var totalMilliseconds = 0, hours, minutes, seconds, milliseconds, parts;
        for (var i = 0, len = times.length; i < len; i++) {
            parts = times[i].split(':');
            hours = parseInt(parts[0], 10) * 3600000;
            minutes = parseInt(parts[1], 10) * 60000;
            seconds = parseInt(parts[2].split('.')[0], 10) * 1000;
            milliseconds = parseInt(parts[2].split('.')[1], 10);
            totalMilliseconds += (hours + minutes + seconds + milliseconds);
        }
        if (!unit || unit.toLowerCase() == 'ms'){
            return totalMilliseconds/times.length + ' milliseconds';
        }
        elseif (unit.toLowerCase() == 's') {
            return (totalMilliseconds/1000)/times.length + ' seconds';
        }

    }
}

// parameters:
// times: an array of timesin your supplied format, 'HH:MM:SS:mm',
// unit: a string ('ms' or 's'), denoting whether to return milliseconds or seconds.
var average = averageTimes(times,'s');
console.log(average);​

JS Fiddle demo.

References:

• for(){/*...*/} loop.
• parseInt().
• split().
• toLowerCase().