I get a variable string like so:
8:45 am
And want, if it is pm, to convert it to 24 hour time. So that I can then drop the am/pm and use it with something else.
I can drop the am/pm quite easily like this:
function replaceEnds(string) {
string = string.replace("am", "");
string = string.replace("pm", "");
return string;
}
But of course if I do that, I don't know if the string is am or pm, so I don't know to add 12 hours on to the string to make it 24 hour.
Anyone know how I could resolve this? I absolutely cannot change the input that I get of the variable, it'll always be the hour (in 12 hour time), minutes, and am or pm.
I get a variable string like so:
8:45 am
And want, if it is pm, to convert it to 24 hour time. So that I can then drop the am/pm and use it with something else.
I can drop the am/pm quite easily like this:
function replaceEnds(string) {
string = string.replace("am", "");
string = string.replace("pm", "");
return string;
}
But of course if I do that, I don't know if the string is am or pm, so I don't know to add 12 hours on to the string to make it 24 hour.
Anyone know how I could resolve this? I absolutely cannot change the input that I get of the variable, it'll always be the hour (in 12 hour time), minutes, and am or pm.
Share Improve this question asked Jul 15, 2013 at 21:21 David GDavid G 6,8714 gold badges32 silver badges51 bronze badges4 Answers
Reset to default 6Using moment.js:
moment(string, 'h:mm a').format('H:mm');
If you want to do it manually, this would be my solution:
function to24Hour(str) {
var tokens = /([10]?\d):([0-5]\d) ([ap]m)/i.exec(str);
if (tokens == null) { return null; }
if (tokens[3].toLowerCase() === 'pm' && tokens[1] !== '12') {
tokens[1] = '' + (12 + (+tokens[1]));
} else if (tokens[3].toLowerCase() === 'am' && tokens[1] === '12') {
tokens[1] = '00';
}
return tokens[1] + ':' + tokens[2];
}
The manual solution is harder to understand, is less flexible, is missing some error checking and needs unit tests. In general, you should usually prefer a well-tested popular library's solution, rather than your own (if a well-tested library is available).
Without using any additional JavaScript libraries:
/**
* @var amPmString - Time ponent (e.g. "8:45 PM")
* @returns - 24 hour time string
*/
function getTwentyFourHourTime(amPmString) {
var d = new Date("1/1/2013 " + amPmString);
return d.getHours() + ':' + d.getMinutes();
}
So for example:
getTwentyFourHourTime("8:45 PM"); // "20:45"
getTwentyFourHourTime("8:45 AM"); // "8:45"
In case you're looking for a solution that converts ANY FORMAT to 24 hours HH:MM correctly.
function get24hTime(str){
str = String(str).toLowerCase().replace(/\s/g, '');
var has_am = str.indexOf('am') >= 0;
var has_pm = str.indexOf('pm') >= 0;
// first strip off the am/pm, leave it either hour or hour:minute
str = str.replace('am', '').replace('pm', '');
// if hour, convert to hour:00
if (str.indexOf(':') < 0) str = str + ':00';
// now it's hour:minute
// we add am/pm back if striped out before
if (has_am) str += ' am';
if (has_pm) str += ' pm';
// now its either hour:minute, or hour:minute am/pm
// put it in a date object, it will convert to 24 hours format for us
var d = new Date("1/1/2011 " + str);
// make hours and minutes double digits
var doubleDigits = function(n){
return (parseInt(n) < 10) ? "0" + n : String(n);
};
return doubleDigits(d.getHours()) + ':' + doubleDigits(d.getMinutes());
}
console.log(get24hTime('6')); // 06:00
console.log(get24hTime('6am')); // 06:00
console.log(get24hTime('6pm')); // 18:00
console.log(get24hTime('6:11pm')); // 18:11
console.log(get24hTime('6:11')); // 06:11
console.log(get24hTime('18')); // 18:00
console.log(get24hTime('18:11')); // 18:11
I've use something similar to this
//time is an array of [hh] & [mm am/pm] (you can get this by time = time.split(":");
function MilitaryTime(time){
if(time[1].indexOf("AM")!=-1){
//its in the morning, so leave as is
return time;
}else if(time[0]!="12"){
//If it is beyond 12 o clock in the after noon, add twelve for military time.
time[0]=String(parseInt(time[0])+12);
return time;
}
else{
return time;
}
}
Once you get your time returned, you can alter the text in any way you want.