Horace Heaven - 1 year ago 141
Javascript Question

# How to calculate average time

how to calculate average time with 11:59:00 PM and 12:00:00 AM so that it can be 11:59:30 PM. currently this code is giving me 11:59:30 AM

``````       var convertTimeToMilliSecondsTest = function(time) {
var startDate = "1970/01/01";
if(time.indexOf("AM") != -1) {
newTime = time.replace("AM", " AM");
} else if(time.indexOf("PM") != -1) {
newTime = time.replace("PM", " PM");
}
var dateString = startDate + " " + newTime;
var date = new Date(dateString.replace(/-/g, '/'));
return date.getTime();
}

var calculateAverageTimeToBed = function(dataset) {
var totalTimeInMilliSeconds = 0;

for(var i = 0;i < dataset.length; ++i) {
totalTimeInMilliSeconds += convertTimeToMilliSecondsTest(dataset[i].startTime);
}

var averageTimeInBed = totalTimeInMilliSeconds / dataset.length;

return averageTimeInBed;
}
``````

This is a function for if you are looking for an average time given a set of times, regardless of date, given a 24 hr period. It works for 12am - 12pm but not 12pm - 12am (because that spans 2 days). If you are spanning days, you must use my first answer which requires the entire date be given in the time being evaluated.

jsFiddle

``````// function will determine average time given a set of
// times in a 24 hr. period, i.e. 12am - 12pm
// it does NOT work for a 24 hr. period from 12pm - 12am
var times = ['11:59:00 AM', '12:00:00 AM'];

// function accepts an array of times as the argument
// requires time to be structured as above
function getAverageTime(times) {
var count = times.length
var timesInSeconds = [];
// loop through times
for (var i =0; i < count; i++) {
// parse
var pieces = times[i].split(':');
var ampm = pieces[2].split(' ');
var hrs = Number(pieces[0]);
var mins = Number(pieces[1]);
var secs = Number(ampm[0]);
var ampm = ampm[1];
// convert to 24 hr format (military time)
if (ampm == 'PM') hrs = hrs + 12;
// find value in seconds of time
var totalSecs = hrs * 60 * 60;
totalSecs += mins * 60;
totalSecs += secs;
timesInSeconds[i] = totalSecs;
}
// find average timesInSeconds
var total = 0;
console.log(timesInSeconds);
for (var j =0; j < count; j++) {
total = total + Number(timesInSeconds[j]);
}
var avg = Math.round(total / count);
console.log('avg secs: '+avg);
// turn seconds back into a time
var avgMins = Math.floor(avg/60);
var avgSecs = avg - (60 * avgMins);
var avgHrs = Math.floor(avgMins/60);
console.log('hours: '+avgHrs);
avgMins = avgMins - (60 * avgHrs);
// convert back to 12 hr. format
var avgAmpm = 'AM';
if (avgHrs > 12) {
avgAmpm = 'PM';
avgHrs = avgHrs - 12;
}