This question already has answers here:
Date difference in years using C# [duplicate]
(18 answers)
Closed 8 years ago.
I need to output the difference between 2 days in years, months and days.
With timespan and subtract i only get the days but is it possible to output in years, months and days.
This is what i have so far:
public string Leeftijdsverschil(DateTime p1, DateTime p2)
{
if (p1 > p2)
{
DateTime verschil = p1.Subtract(TimeSpan.FromTicks(p2.Ticks));
return verschil.ToString();
}
else
{
DateTime verschil = p2.Subtract(TimeSpan.FromTicks(p1.Ticks));
return verschil.ToString();
}
}
The .NET types don't give you a decent answer to this without having to write code to try one answer and adjust appropriately, but my Noda Time project is designed to handle this sort of thing. For example:
LocalDate x = new LocalDate(2013, 5, 21);
LocalDate y = new LocalDate(2014, 12, 15);
Period p = Period.Between(x, y);
Console.WriteLine("{0} {1} {2}", p.Years, p.Months, p.Days);
Result:
1 6 24
(i.e. 1 year, 6 months and 24 days)
If you decide to use Noda Time for this, you could just do it within your method, using DateTime elsewhere and converting between the types... but it would generally be better to embrace Noda Time more widely. The aim is for it to allow your code to be clearer than just using DateTime.
To get the delta, just subtract directly:
var delta = p1 - p2;
This gives you a TimeSpan. From there, you have access to .Days. Months and years, however, are much more complicated. If you want the difference in those terms, you'll have to compare the properties of p1 and p2 directly (or: as Jon says: use Noda Time)
Related
This question already has an answer here:
Get days as an int from a timespan?
(1 answer)
Closed 4 years ago.
Is it possible to compare a timespan to an integer in C#?
if say I want to know if a timespan is equal to 30 days, and if it is then do something?
There is the property TotalDays
There's also TotalHours, TotalMinutes, TotalSeconds and TotalMilliseconds. You should check out the TimeSpan-properties for more information
You can use the property Days of the TimeSpan object, which returns the days component of the time interval
if (ts.Days == 30)
{
// do something
}
TimeSpan t = new TimeSpan();
if(t.TotalDays==30)
{
//Do Something
}
This question already has answers here:
C# Short Error: Negating the minimum value of a twos complement number is invalid
(4 answers)
Closed 9 years ago.
I get a strange error on this little snippet:
private int CalculateDifference(DateTime date1, DateTime date2)
{
var difference = date1 - date2;
return Math.Abs((int)difference.TotalSeconds);
}
In my case I'm calculating a difference of 3520789176.4909997 total seconds. The program throws an exception I´ve never seen in ten years of C# coding:
System.OverflowException: "Negating the minimum value of a twos complement number is invalid."
I´m pretty sure it´s related to floating point arithmetics, but I don´t understand the details and I just need a sufficient solution to determine the difference of the two date values.
The problem is that the when the a double exceeds the range of values that can be expressed in an int—which is -2,147,483,648 to 2,147,483,647, the result is undefined according to the C# specification (See Jeppe Stig Nielsen's comment below), but in the .NET implementation, is int.MinValue. So when you convert difference to an int, it takes the value, -2,147,483,648 which then cannot be negated using Math.Abs
If you convert this method to use long instead, it should work:
private long CalculateDifference(DateTime date1, DateTime date2)
{
var difference = date1 - date2;
return Math.Abs((long)difference.TotalSeconds);
}
You could also solve this by simply converting to int after you've taken the absolute value:
private int CalculateDifference(DateTime date1, DateTime date2)
{
var difference = date1 - date2;
return (int)Math.Abs(difference.TotalSeconds);
}
According to msdn: value of Int.Maxvalue is 2,147,483,647
Your number seems to be greater than that.
This question already has answers here:
What is the best way to divide two TimeSpan objects?
(4 answers)
Closed 5 years ago.
I have a value in TimeSpan, let's say: tsp1 = 2 hour 5 minutes.
I have another TimeSpan variable which contains a value like: tsp2 = 0 hours 2 minutes
Please tell me how I can divide tsp1 by tsp2 so that I can get the exact number of times tsp2 divides into tsp1 and what the remainder is.
I am using Visual Studio 2008.
Thanks.
The simplest approach is probably just to take their lengths in ticks, and divide those. For example:
long ticks1 = tsp1.Ticks;
long ticks2 = tsp2.Ticks;
long remainder;
long count = Math.DivRem(ticks1, ticks2, out remainder);
TimeSpan remainderSpan = TimeSpan.FromTicks(remainder);
Console.WriteLine("tsp1/tsp2 = {0}, remainder {1}", count, remainderSpan);
a div b:
double adivb = (double)a.Ticks/b.Ticks;
edited:
i found another post on th same topic
How can I achieve a modulus operation with System.TimeSpan values, without looping?
An int will hold enough seconds for ~64 years, so as long as you stay well below that:
int count = (int) (tsp1.t.TotalSeconds / tsp2.t.TotalSeconds);
double remainder = tsp1.t.TotalSeconds - (count * tsp2.t.TotalSeconds);
And maybe convert the remainder to int as well.
This question already has answers here:
Closed 12 years ago.
Possible Duplicate:
How do I calculate someone’s age in C#?
I want to calculate basically the age of employees - So we have DOB for each employee, So on
the C# Side I want to do something like this -
int age=Convert.Int32(DateTime.Now-DOB);
I can use days and manipulate then get the age...but I wanted to know if there something I can use directly to get the number of years.
Do you want calculate the age in years for an employee? Then you can use this snippet (from Calculate age in C#):
DateTime now = DateTime.Today;
int age = now.Year - bday.Year;
if (bday > now.AddYears(-age)) age--;
If not, then please specify. I'm having a hard time understanding what you want.
Subtracting two DateTime gives you a TimeSpan back. Unfortunately, the largest unit it gives you back is Days.
While not exact, you can estimate it, like this:
int days = (DateTime.Today - DOB).Days;
//assume 365.25 days per year
decimal years = days / 365.25m;
Edit: Whoops, TotalDays is a double, Days is an int.
On this site they have:
public static int CalculateAge(DateTime BirthDate)
{
int YearsPassed = DateTime.Now.Year - BirthDate.Year;
// Are we before the birth date this year? If so subtract one year from the mix
if (DateTime.Now.Month < BirthDate.Month || (DateTime.Now.Month == BirthDate.Month && DateTime.Now.Day < BirthDate.Day))
{
YearsPassed--;
}
return YearsPassed;
}
private static Int32 CalculateAge(DateTime DOB)
{
DateTime temp = DOB;
Int32 age = 0;
while ((temp = temp.AddYears(1)) < DateTime.Now)
age++;
return age;
}
Math.Round(DateTime.Now.Subtract(DOB).TotalDays/365.0)
As pointed out, this won't work. You'd have to do this:
(Int32)Math.Round((span.TotalDays - (span.TotalDays % 365.0)) / 365.0);
and at that point the other solution is less complex and continues to be accurate over larger spans.
Edit 2, how about:
Math.Floor(DateTime.Now.Subtract(DOB).TotalDays/365.0)
Christ I suck at basic math these days...
(DateTime.Now - DOB).TotalDays/365
Subtracting a DateTime struct from another DateTime struct will give you a TimeSpan struct which has the property TotalDays... then just divide by 365
I want to round a DateTime to the nearest 5 seconds. This is the way I'm currently doing it but I was wondering if there was a better or more concise way?
DateTime now = DateTime.Now;
int second = 0;
// round to nearest 5 second mark
if (now.Second % 5 > 2.5)
{
// round up
second = now.Second + (5 - (now.Second % 5));
}
else
{
// round down
second = now.Second - (now.Second % 5);
}
DateTime rounded = new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute, second);
Please note that I've found these two previous questions, however they truncate rather than round the time.
(Sorry for the resurrection; I recognize it's an old and answered question - just adding some extra code for Google's sake.)
I started with JayMcClellan's answer, but then I wanted it to be more generic, rounding to arbitrary intervals (not just 5 seconds). So I ended up leaving Jay's method for one that uses Math.Round on ticks and put it into an extension method that can take arbitrary intervals and also offers the option of changing the rounding logic (banker's rounding versus away-from-zero). I'm posting here in case this is helpful to someone else as well:
public static TimeSpan Round(this TimeSpan time, TimeSpan roundingInterval, MidpointRounding roundingType) {
return new TimeSpan(
Convert.ToInt64(Math.Round(
time.Ticks / (decimal)roundingInterval.Ticks,
roundingType
)) * roundingInterval.Ticks
);
}
public static TimeSpan Round(this TimeSpan time, TimeSpan roundingInterval) {
return Round(time, roundingInterval, MidpointRounding.ToEven);
}
public static DateTime Round(this DateTime datetime, TimeSpan roundingInterval) {
return new DateTime((datetime - DateTime.MinValue).Round(roundingInterval).Ticks);
}
It won't win any awards for bare efficiency, but I find it easy to read and intuitive to use. Example usage:
new DateTime(2010, 11, 4, 10, 28, 27).Round(TimeSpan.FromMinutes(1)); // rounds to 2010.11.04 10:28:00
new DateTime(2010, 11, 4, 13, 28, 27).Round(TimeSpan.FromDays(1)); // rounds to 2010.11.05 00:00
new TimeSpan(0, 2, 26).Round(TimeSpan.FromSeconds(5)); // rounds to 00:02:25
new TimeSpan(3, 34, 0).Round(TimeSpan.FromMinutes(37); // rounds to 03:42:00...for all your round-to-37-minute needs
The Ticks count of a DateTime represents 100-nanosecond intervals, so you can round to the nearest 5 seconds by rounding to the nearest 50000000-tick interval like this:
DateTime now = DateTime.Now;
DateTime rounded = new DateTime(((now.Ticks + 25000000) / 50000000) * 50000000);
That's more concise, but not necessarily better. It depends on whether you prefer brevity and speed over code clarity. Yours is arguably easier to understand.
Like you mentioned, it's fairly easy to truncate. So, just add 2.5 seconds, then truncate down.
I can't think of a better way, although I would probably factor out the round method:
static int Round(int n, int r)
{
if ((n % r) <= r / 2)
{
return n - (n % r);
}
return n + (r - (n % r));
}
Also, % returns an int, so comparing it to 2.5 strikes me as a little odd, even though it is correct. I'd use >= 3.
How about this (blending a few answers together)? I think it conveys the meaning well and should handle the edge cases (rounding to the next minute) elegantly due to AddSeconds.
// truncate to multiple of 5
int second = 5 * (int) (now.Second / 5);
DateTime dt = new DateTime(..., second);
// round-up if necessary
if (now.Second % 5 > 2.5)
{
dt = dt.AddSeconds(5);
}
The Ticks approach as shown by Jay is more concise, but may be a bit less readable. If you use that approach, at least reference TimeSpan.TicksPerSecond.
I couldn't recognize the difference between C# and a bar of soap (well, I couldn't when I originally wrote this answer, things have changed quite a bit in the years since) but, if you're looking for a more concise solution, I would just put the whole thing in a function - there's little that will be more concise in your code than a simple call to said function:
DateTime rounded = roundTo5Secs (DateTime.Now);
Then you can put whatever you want in the function and just document how it works, such as (assuming these are all integer operations):
secBase = now.Second / 5;
secExtra = now.Second % 5;
if (secExtra > 2) {
return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute,
secBase + 5);
}
return new DateTime(now.Year, now.Month, now.Day, now.Hour, now.Minute,
secBase);
You may also need some extra checks if secBase goes to 60 (unless C# DateTime objects are smart enough to bump up the minute (and hour if minute goes to 60, and so on).
Technically, you can never correctly round to an odd interval given only seconds.
2, 4, 6, 8, 10 <-- are no problem
If you are 'distributing' times in intervals and if the jitter is low, truncation is a lot
more tractable.
If you can pass milliseconds and round at a 500mS mark, you will be able to to odd
seconds and also slash the effect of jitter way down or eliminate it entirely.
Most simple and accurate one-liner:
private static DateTime QuantizeToEachNthSecond(DateTime dateTime, int nthSecond = 5)
{
return dateTime.AddTicks(-(dateTime.Ticks % (nthSecond * TimeSpan.TicksPerSecond)));
}
so, if you like each 5th second, if will be truncated to e.g. "10:12:02" -> "10:12:00", "10:12:08" -> "10:12:05" and so on.