Develop Reference

How to subtract time (HHH:MM)

I want to Subtract two time strings that I read from an excel sheet, for example 150:24 and 124:30.
The time format is HHH:MM in the excel sheet. How can I subtract these two strings in C#?
I can not illustrate the data format! also I can not write true code for this issue.

You can calculate the times difference based on minutes. Then convert to any format you want...
var s1 = "150:24".Split(':');
var s2 = "124:30".Split(':');
var diffMinutes= int.Parse(s1[0]) * 60 + int.Parse(s1[1]) - int.Parse(s2[0]) * 60 - int.Parse(s2[1]);
Console.WriteLine("difference in minutes: " +diffMinutes);
//difference in minutes: 1554
Console.WriteLine("difference in HHH:MM: "+ diffMinutes/60 + ":"+diffMinutes%60);
//difference in HHH:MM: 25:54
TimeSpan t= TimeSpan.FromMinutes(result);
Console.WriteLine(t);
//1.01:54:00

TimeSpan.Parse unfortunately does not work is the hour part is > 23. But of course it is possible to split on the ':', convert the hour and minute parts to integers separately and construct a TimeSpan from it:
public static TimeSpan ParseHoursAndMinutes(string s)
{
// NOTE: no error checking!
var parts = s.Split(':');
var hours = int.Parse(parts[0]);
var minutes = int.Parse(parts[1]);
return new TimeSpan(hours, minutes, 0);
}
var diff = ParseHoursAndMinutes("150:24") - ParseHoursAndMinutes("124:30");
Console.WriteLine(diff); // => 1.01:54:00

Converting minutes to hours only

I’m trying to solve this problem :
I’ve a large amount of minutes and I want to convert them into hours only, when I try with TimeSpan, it always shows days and hours.
My example code :
double minutes = 2000 ;
TimeSpan hours = TimeSpan.FromMinutes(minutes);
label1.Text = hours.ToString(#"hh\:mm");
The output result is 09:20 but I wanted this result 33:20
How can I convert minutes to get exact numbers of hours ?

This code produces the 33:20 result you're asking:
double minutes = 2000;
TimeSpan ts = TimeSpan.FromMinutes(minutes);
var res = $"{(int)ts.TotalHours}:{ts.Minutes}";

You need to use TotalHours on the TimeSpan object.
string.Format("{0}:{1}",
(int) hours.TotalHours,
hours.Minutes);

Yet another possibility is to use 0 and 00 formatting strings in order to combine formatting and truncating:
double minutes = 2000;
// 2000 -> 33:20
// 1808 -> 30:08
// 8 -> 0:08
label1.Text = $"{minutes/60:0}:{minutes%60:00}";
If minutes can be negative, you should add Math.Abs:
// -2000 -> -33:20
label1.Text = $"{minutes/60:0}:{Math.Abs(minutes)%60:00}";

public static void Main()
{
//assigning values to variable
double minutes = 2000;
TimeSpan tspan = TimeSpan.FromMinutes(minutes); //converting minutes to timespan
string res1 = (int)tspan.TotalHours +" Hours " + tspan.Minutes +" Minutes";
string res2= (int)tspan.TotalHours + ":"+tspan.Minutes;
string res3= Convert.ToInt32(tspan.TotalHours) + "."+tspan.Minutes +" Hours";
Console.WriteLine(res1);
Console.WriteLine(res2);
Console.WriteLine(res3);
}
Output:
33 Hours 20 Minutes
33:20
33.20 Hours

Do it manually and use
string.Format("{0:D2}:{1:D2}",(int)minutes/60, (int)minutes%60)
or without casting:
string.Format("{0:00}:{1:00}", minutes/60, minutes%60)
Since C#6 with String Interpolation:
$"{minutes/60:00}:{minutes%60:00}"

How can I parse minutes to seconds?

I want to parse the following input "10:05" in format "minutes:seconds" in seconds. So 10:05 should be 10 * 60 = 600 + 5 = 605. How can I manage to do this with code ?

Just split the string, parse the numbers, and do your calculation:
string s = "10:05";
var parts = s.Split(':');
int seconds = int.Parse(parts[0]) * 60 + int.Parse(parts[1]);
Console.WriteLine(seconds); // 605
You can also use TimeSpan.Parse in this case which is able to parse this format if you add a hour part in front of it. You can then use the TotalSeconds property to get your desired result:
double seconds = TimeSpan.Parse("00:" + s).TotalSeconds;
Console.WriteLine(seconds); // 605

#poke is close, but you asked for seconds, thus:
string s= "10:05";
double seconds = TimeSpan.Parse("00:" + s).TotalSeconds;
Returns 605.

There are many ways to do this. Here are just a couple. If you know that the format is always going to be mm:ss then you could use the TimeSpan class, the ParseExact method, and the TotalSeconds property. Here's an example of how you could do it.
TimeSpan ts = TimeSpan.ParseExact(mytime, "mm:ss", System.Globalization.CultureInfo.InvariantCulture);
double seconds = ts.TotalSeconds;
If you have a bunch of different formats that can show up you can use the ParseExact and provide multiple time formats. Here's an example that takes a few formats.
//HH -> 24 hour format always with 2 digits ("08" = 8 hours)
// H -> 24 hour format with as few digits as possible ("8" = 8 hours)
//mm -> minutes always with 2 digits ("08" = 8 minutes)
// m -> minutes with as few digits as possible ("8" = 8 minutes)
//ss -> seconds always with 2 digits ("08" = 8 seconds)
// s -> seconds with as few digits as possible ("8" = 8 seconds)
string[] formats = new string["HH:mm:ss", "H:mm:ss", "mm:ss", "m:ss", "ss", "s"];
TimeSpan ts = TimeSpan.ParseExact(mytime, formats, System.Globalization.CultureInfo.InvariantCulture);
double seconds = ts.TotalSeconds;
Here's a link to the MSDN documentation for the TimeSpan class. Check out the Methods and Properties for the TimeSpan class. Here's a link on formatting time strings.
The other way is to manually split the input string into the two parts and use the Convert class to convert each part into integers or doubles.
string[] timeparts = mytime.Split(':');
string minstr = timeparts[0];
string secstr = timeparts[1];
int mins = Convert.ToInt32(minstr);
int secs = Convert.ToInt32(secstr);
int seconds = mins * 60 + secs;
Here's the documentation for the Convert class.

Calculate total number of Hours asp.net c#

I have done the following piece of code to add the Hours and thus calculate total number of hours.
string hour1="48.40";
string hour2 = "45.35";
TimeSpan ts = new TimeSpan(int.Parse(hour1.Split('.')[0]),int.Parse(hour1.Split('.')[1]),
0);
TimeSpan ts1 = new TimeSpan(int.Parse(hour2.Split('.')[0]),int.Parse(hour2.Split('.')[1]),
0);
Double total = (ts.TotalHours) + (ts1.TotalHours);
The problem here is when i add hour1 and hour2 the total comes as 64.25 which actually should have been 64.15
This is just one of the test case, if i put hour1= 40.00 and hour2= 40.10 than the value in the total comes as 80.166666666666657 which actually should have been 80.10
can anyone help me understand what am i doing wrong and what is the correct way to add HOUR and get total number of hours ?

Actually you're getting correct result - just mixing minutes and fractional parts of hours.
80 hrs 10 mins is 80 1/6 hours
64 hours 15 mins is 64 1/4 hours

It gets a little strange when you have timestamps put into strings. But if you need to do it like this, this code should work
string hour1="48.40";
string hour2 = "45.35";
//find total number of minutes for each hour above
int minutes1 = int.Parse(hour1.Split('.')[0])*60+int.Parse(hour1.Split('.')[1]);
int minutes2 = int.Parse(hour2.Split('.')[0])*60+int.Parse(hour2.Split('.')[1]);
//calculate back to hours and minutes and reassemble as a string
string result = (minutes1+minutes2)/60+"."+(minutes1+minutes2)%60;
And I hope you are expecting 94.15 and not 64.15 in your example above.

You may use next code to get result you would like to:
string hour1 = "48.40";
string hour2 = "45.35";
TimeSpan ts = new TimeSpan(int.Parse(hour1.Split('.')[0]), int.Parse(hour1.Split('.')[1]),
0);
TimeSpan ts1 = new TimeSpan(int.Parse(hour2.Split('.')[0]), int.Parse(hour2.Split('.')[1]),
0);
TimeSpan total = ts + ts1;
int hours = (int)total.TotalHours;
int minutes = total.Minutes;

Work out min and hours

I have a minute value and i want to have to 2 string values one with how many hours and the other with the minutes, e.g.:
Value - 121 minutes
string hours = 2
string minutes = 1
Value - 58 minutes
string hours = 0
string minutes = 58
How can I work this out in C#?

var span = System.TimeSpan.FromMinutes(121);
var hours = ((int)span.TotalHours).ToString();
var minutes = span.Minutes.ToString();
The ToString() is because you asked for string values ...
TotalHours are the complete hours in the TimeSpan, they can be more than 24 (whereas the "Hours" field has a maximum of 24)
Oh, and on second thought: Why use the TimeSpan and not calculate it yourself? Because TimeSpan is already there debugged & tested by Microsoft, it has a nice clean interface (looking at the code you easily see whats going on without having to follow a calculation mentally) and it easily extends to further solutions. (Have the input in seconds? Use TimeSpan.FromSeconds(). Want the days? Use span.TotalDays ...)
Update:
I just noticed mistake in my answer: TotalHours returns a fractional value of all the hours, so we have to truncate it to an integer before converting it to a string.

Use a Timespan struct and its Parse method.

int value = 121;
int hours = value / 60; // 2
int minutes = value % 60; // 1
string strHours = hours.ToString();
string strMinutes = minutes.ToString();

int value = 121;
int hours = value / 60;
int minutes = value % 60;

int value = 121;
TimeSpan timeSpan = TimeSpan.FromMinutes(value);
// gives you the rounded down value of 2
int hours = timeSpan.Hours;
// gives you the minutes left of the hour
int minutes = value - (hours * 60);