Javascript: How to turn the time (stored as a fraction) into a readable string?
I have the time stored as a fraction (done so it can be displayed on a graph), e.g. 15.5 is 3.30pm and 23.25 is 11.15pm. I need to turn those num开发者_如何学Pythonbers into strings in the format HH:MM:SS. Is there a simple way of doing this?
var fraction = 23.5;
var date = new Date(2000, 1, 1); // use any date as base reference
date.setUTCSeconds(fraction * 3600); // add number of seconds in fractional hours
Then use a date formatting script such as this, or Date.js if you're not fond or formatting and padding.
date.format("HH:MM:ss"); // 23:30:00
See an example. I'm using the formatting function from here.
Something like this ?
var fraction = 14.5;
var hours = Math.floor(fraction); // extract the hours (in 24 hour format)
var mins = 60 * (fraction - hours); // calculate the minutes
t = new Date(); // create a date/time object
t.setHours(hours); // set the hours
t.setMinutes(mins); // set the mins
console.log(t.toTimeString()); //show it
or completely manual
var fraction = 14.5;
var hours = Math.floor(fraction);
var mins = 60 * (fraction - hours);
var ampm = ((fraction % 24) < 12) ? 'am' : 'pm';
formatted = ('0' + hours % 12).substr(-2) + ':' + ('0' + mins).substr(-2) + ':00 ' + ampm;
console.log(formatted);
Update
And a version with seconds as well..
var fraction = 14.33;
var hours = Math.floor(fraction);
var allseconds = 3600 * (fraction - hours);
var minutes = Math.floor(allseconds / 60);
var seconds = Math.floor(allseconds % 60);
var ampm = ((fraction % 24) < 12) ? 'am' : 'pm';
formatted = ('0' + hours % 12).substr(-2) + ':' + ('0' + minutes).substr(-2) + ':' + ('0' + seconds).substr(-2) + ' ' + ampm;
console.log(formatted);
Manual function:
var time = function(num) {
if(num < 0 || num >= 24) {throw "Invalid number");}
var x = num > 13 ? num - 12 : num;
var h = Math.floor(x);
var min = x - h;
var ampm = num >= 12 && num < 24 ? "pm" : "am";
return (h + ":" + Math.floor(min * 60) + ampm);
};
Tests:
time(13.40); // 1:24pm
time(11.25); // 11:15pm
time(12.50); // 12:30pm
time(23.50); // 11:30pm
time(0.50); // 0:30am
time(24.00); // error!!
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