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I want to calculate the time in hours and minutes between two dates. But also subtract certain hours and dates in that period.
Example:
DateTime startDate = new DateTime(2022,10,8,14,35,1)
DateTime endDate = new DateTime(2022,11,1,17,46,62)
With:
Timespan ts = endDate.Subtract(starDate);
I get the whole timespan between the dates.
But I want to subtract all the time between:
00:OO - 08:00 on all days
19:00 - 24:00 on all days
00:00 — 24:00 Saturdays and Sundays
00:00 - 24:00 on specific dates
I can get the correct results for this but not very efficient.
Pseudo code:
int seconds = 0
while(startDate <= endDate)
{
if(startDate not in excludedTime)
seconds++;
startDate = startDate.AddSeconds(1);
}
There must be a more efficent way of doing this?
One idea is to write one method that will adjust a date based on the weekend/holiday rules, another to get the timespan from a day based on the working hour rules, and then a third that utilizes these to add up the timespans for each day in a range.
For the first method, I've added a bool forward argument that we can set to false for adjusting the end date, since presumably the implementation of moving a date backwards is slightly different. Note that when moving a day to a new day, I use the .Date property of the result to reset the time information:
public static DateTime AdjustDate(DateTime input, bool forward = true)
{
var skipDates = new List<DateTime>
{
// add a comma-separated list of dates to skip here
};
while (skipDates.Contains(input.Date))
input = input.AddDays(forward ? 1 : -1).Date;
if (input.DayOfWeek == DayOfWeek.Saturday)
input = input.AddDays(forward ? 2 : -1).Date;
if (input.DayOfWeek == DayOfWeek.Sunday)
input = input.AddDays(forward ? 1 : -2).Date;
return input;
}
Once we have that method working, we need one that will get us the timespan for just the specific working hours of that day. Once again we have a bool argument that specifies if we're counting hours FROM the start of the day or TO the end of the day. Then we can add logic to adjust the actual hour of the date and do our math based on the specified start and end hours for a day.
public static TimeSpan GetNetTimeSpan(DateTime input, bool fromStart = true)
{
if (input.Hour > 19)
{
if (fromStart)
input = new DateTime(input.Year, input.Month, input.Day, 19, 0, 0);
else return TimeSpan.Zero;
}
if (input.Hour < 8)
{
if (fromStart) return TimeSpan.Zero;
else input = new DateTime(input.Year, input.Month, input.Day, 8, 0, 0);
}
if (fromStart)
{
return input - new DateTime(input.Year, input.Month, input.Day, 8, 0, 0);
}
else
{
return new DateTime(input.Year, input.Month, input.Day, 19, 0, 0) - input;
}
}
With these in place, we should now be able to loop through all the days and create a timespan that encapsulates the valid ticks of each day:
public static TimeSpan GetNetDifference(DateTime start, DateTime end)
{
// First, adjust our start and end dates to avoid weekends and holidays
start = AdjustDate(start);
end = AdjustDate(end, false);
// If our start is no longer less than our end, return zero
if (start >= end) return TimeSpan.Zero;
// Begin with the start date timespan
var result = GetNetTimeSpan(start);
// Next loop through each day between start and end and add them to the result
var current = AdjustDate(start.AddDays(1).Date);
while(current.Date < end.Date)
{
result += GetNetTimeSpan(current);
current = AdjustDate(current.AddDays(1).Date);
}
// Add our last day and return the result
return result + GetNetTimeSpan(end);
}
I haven't tested it, partly because it's not completely clear if this follows your rules, but it should give you a good starting point.
Also, it would be more flexible if we parameterized the start and end times rather than having them hard-coded at 8 and 19.
Related
I am trying to develop a simple app for my upskill for c#, however I am stuck and new to the functionality of time with c#,
what I need:
I have a 3 text boxes that will contain start time, end time and time interval.
say user entered 7:00 AM , 12:00 PM , and 60 minutes it will store it inside a datatable and add it inside a listbox.
7:00 AM
8:00 AM
9:00 AM
10:00 AM
11:00 AM
12:00 AM
current approach:
I think I need to use the DateTime.AddMinutes(interval) but how am I going to arrive to the logic of it will stop if it reaches the end time? using the DateTime method? I am really confused on what to use, I saw TimeRange, TimeSpan etc.
You can use TimeSpan and DateTime together (to calculate and print respectively)
TimeSpan start = DateTime.Parse("7:00 AM").TimeOfDay;
TimeSpan end = DateTime.Parse("12:00 PM").TimeOfDay;
TimeSpan interval = new TimeSpan(0, 60, 0);
// If Start is bigger than end, Add a day to the end.
if (start > end)
end = end.Add(new TimeSpan(1, 0, 0, 0));
while (true)
{
Console.WriteLine((new DateTime() + start).ToString("hh:mm tt"));
start = start.Add(interval);
if (start > end)
break;
}
Output looks like this,
07:00 AM
08:00 AM
09:00 AM
10:00 AM
11:00 AM
12:00 PM
MS Documentation on TimeSpan
You can use TimeSpan with boolean logical operator to test if the currentTime is less than your endTime.
Below is example code.
TimeSpan startTime;
int interval;
TimeSpan tInterval = new TimeSpan(interval, 0, 0);
TimeSpan endTime;
TimeSpan currentTime = startTime;
while( (currentTime = startTime + tInterval) <= endTime)
{
// add currentTime to list box
}
This should take care of the issue with the End Times being "earlier" than the Start Time:
private static void TestTimeSpan()
{
int minutes = 60;
var interval = new TimeSpan(0,minutes,0);
TimeSpan start = DateTime.Parse("7:00 PM").TimeOfDay;
TimeSpan end = DateTime.Parse("1:00 AM").TimeOfDay;
//End of input data--start of solution
var diffSpan = end - start;
var diffMinutes = diffSpan.TotalMinutes > 0 ? diffSpan.TotalMinutes : diffSpan.TotalMinutes + (60 * 24);
var myTimeList = new List<TimeSpan>();
for(int i = 0; i < diffMinutes + minutes; i += minutes)
{
myTimeList.Add(start);
start = start.Add(interval);
}
myTimeList.ForEach(x => Console.WriteLine((new DateTime() + x).ToString("hh:mm tt")));
}
EDIT
Creating a sequence of Time values based in two input times and an interval is straight forward until the "start time" is earlier than the "end time", because just checking to see if the "end time" is greater than the start time fails your algorithm immediately.
This code utilizes the fact that there are only 24 hours in the day. Since the interval value is given in minutes, we can use that to section those minutes into "steps" of time. This code proceeds to step through each interval in time and capture the time at that step and save that in a List of TimeSpan (the captured value could easily be of type string--formatted as desired).
The trick here is when the "end time" is earlier than the "start time" we get a negative TimeSpan which is then used to calculate the steps to the "end time" on the next day. This is where the (60 * 24) [60 minutes x 24 hrs] part comes in to create the correct "diffMinutes" using a ternary operator.
After that the code simple iterates over the List "myTimeList" to write the formatted TimeSpan to the console. However, this 'List' is just a portable collection that can be sent anywhere in you code to do anything needed.
There are lots of other solutions, this one just seems straightforward, to me.
I run into this question of how to determine if DateTime.UtcNow (e.g. 2018-01-01T20:00:00Z) falls within the given range of days and times that are in another timezone. There are no specific dates given, just the days of the week, and the time of the day. The given time is in ISO 8601 standard format.
To simplify this question, it can be how to check if a UTC time is within business hours in China.
For example, the given day and time range is given by someone form China in time zone +08:00, it can be: FromDayOfWeek = "Friday", FromTimeOfDay = "17:00:00+8:00", ToDayOfWeek = "Monday", ToTimeOfWeek = "08:00:00+8:00". I need to determine if "now" in China is sometime between the given range (Friday 17:00:00+8:00 - Monday 08:00:00+8:00).
I'm stuck at how to convert the DateTime and get the day of the week in that local time, since 2018-01-01T20:00:00Z is Monday in UK, but at the same time, since China is +08:00, it is already Tuesday in China.
My approach:
// parse the time to get the zone first (+08:00)
TimeSpan ts = TimeSpan.Parse("-08:00");
// Create a custom time zone since the time zone id is not given, and cannot be searched by SearchTimeZoneById
TimeZoneInfo tzi = TimeZoneInfo.CreateCustomTimeZone(zoneId, ts, displayName, standardName);
DateTime localDateTime = TimeZoneInfo.ConvertTime(Date.UtcNow, tzi);
String localDay = localDateTime.DayOfWeek;
// Determine if localDay is between FromDayOfWeek and ToDayOfWeek
// cast the days to integers from 1 (Monday) to 7 (Sunday)
// create an array of days in integar days = [5, 6, 7, 1]
// if days.contains(localDays), check the times
...
Can anyone suggest some better solutions? I am not sure if mine works, and there are holes in how to deal with Day Light Saving time, since the zone will change, and how to check the time range. I am new to C#, any suggestions of libraries I can use is great!
Instead of converting both start and end times from UTC, just convert the other time into UTC
TimeZoneInfo chinaTimeZone = TimeZoneInfo.CreateCustomTimeZone(zoneID, TimeSpan.Parse("-08:00"), displayName, standardName);
DateTime FromTime = new DateTime(2018, 0, 19, 13, 0, 0); // year, month, day, hour, minute, second : Friday 1pm
DateTime ToTime = new DateTime(2018, 0, 21, 1, 0, 0); // year, month, day, hour, minute, second : Monday 1am
DateTime nowinUTC = DateTime.UtcNow;
DateTime nowInChina = TimeZoneInfo.ConvertTimeFromUtc(nowinUTC, chinaTimeZone);
if(FromTime< nowInChina && ToTime> nowInChina)
{
// Time is within the from and two times
}
Per the comments on #Moffen's answer, you only want to check if Now is within a specific DayOfWeek range:
public void CheckAll(List<SomeClass> spans)
{
var chinaTZ = TimeZoneInfo.CreateCustomTimeZone(zoneID, TimeSpan.Parse("-08:00"), displayName, standardName);
var nowInChina = TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, chinaTZ);
foreach ( var span in spans )
{
if (InRange(nowInChina, span.startDay, span.endDay))
// Do something on success
// Check for valid times here
;
else
// Do something on Failure
;
}
}
public bool InRange(DateTime dateToCheck, DayOfWeek startDay, DayOfWeek endDay)
{
// Initialise as one day prior because first action in loop is to increment current
var current = (int)startDay - 1;
do
{
// Move to next day, wrap back to Sunday if went past Saturday
current = (current + 1) % 7;
if (dateToCheck.DayOfWeek == (DayOfWeek)current)
return true;
} while (current != (int)endDay);
return false;
}
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How do i go about creating a datetime based on only the following information:
Day of Week, Hour & Minuet.
I.e. I don't care what month it is or even what the date is (i don't have that info in the database).
I thought i could parse them as a string but is turning out to be more difficult than i thought.
Created on function for you it might be helpful to you ..
public DateTime CreateDayOfWeek(int DayOfWeek,int hour,int min)
{
DateTime dt = new DateTime(DateTime.Now.Year,DateTime.Now.Month,DateTime.Now.Day,hour,min,0);
// The (... + 7) % 7 ensures we end up with a value in the range [0, 6]
int daysUntilTuesday = (DayOfWeek - (int)dt.DayOfWeek + 7) % 7;
// DateTime nextTuesday = today.AddDays(daysUntilTuesday);
dt = dt.AddDays(daysUntilTuesday);
return dt;
}
I have tested for several dates and its working for me ..
let me know if you have any issue ..
Here is .netFiddle
You can create your date like this...
var hour = 1; // you set this from code
var minute = 1; // set this from code
var now = DateTime.Now;
var tempDateTime = new DateTime(now.Year, now.Month, now.Day, hour, minute, 0);
// Make this enum whatever you want your date to be...
var num = (int)DayOfWeek.Sunday;
var dateForComparison = tempDateTime.AddDays(num - (int)tempDateTime.DayOfWeek);
Now dateForComparison holds a date that has your time values set and the day of week you have specified.
You said you don't care about what month or date it is, which makes me assume you want any date as long as it is the right day of week and time (hour and minute). You can do it like this:
var date = new System.DateTime(2016, 9, 25);
date = date.AddDays(dow).AddHours(hours).AddMinutes(minutes);
September 25, 2016 was a Sunday. Add the day of the week (Sunday = 0) and you get the correct day. Then add the hours and minutes. Of course, if you like you can pick any Sunday of any month/year to start.
You can create a function for build your date:
public DateTime BuildDate(Int32 day, Int32 hour, Int32 minute)
{
var now = DateTime.Now;
var initialDate = now.AddDays(((Int32)now.DayOfWeek + 1) * -1);
return new DateTime(initialDate.Year, initialDate.Month, initialDate.AddDays(day).Day, hour, minute, 0);
}
The day of week is start from sunday in this case.
You can use: DateTime.ToString Method (String)
DateTime.Now.ToString("ddd HH:mm") // for military time (24 hour clock)
More: https://msdn.microsoft.com/en-us/library/8kb3ddd4.aspx
I want to compare a given date to today and here is the condition: If provided date is greater than or equal to 6 months earlier from today, return true else return false
Code:
string strDate = tbDate.Text; //2015-03-29
if (DateTime.Now.AddMonths(-6) == DateTime.Parse(strDate)) //if given date is equal to exactly 6 months past from today (change == to > if date has to be less 6 months)
{
lblResult.Text = "true"; //this doesn't work with the entered date above.
}
else //otherwise give me the date which will be 6 months from a given date.
{
DateTime dt2 = Convert.ToDateTime(strDate);
lblResult.Text = "6 Months from given date is: " + dt2.AddMonths(6); //this works fine
}
If 6 months or greater than 6 months is what I would like for one
condition
If less than 6 months is another condition.
Your first problem is that you're using DateTime.Now instead of DateTime.Today - so subtracting 6 months will give you another DateTime with a particular time of day, which is very unlikely to be exactly the date/time you've parsed. For the rest of this post, I'm assuming that the value you parse is really a date, so you end up with a DateTime with a time-of-day of midnight. (Of course, in my very biased view, it would be better to use a library which supports "date" as a first class concept...)
The next problem is that you are assuming that subtracting 6 months from today and comparing it with a fixed date is equivalent to adding 6 months to the fixed date and comparing it with today. They're not the same operation - calendar arithmetic just doesn't work like that. You should work out which way you want it to work, and be consistent. For example:
DateTime start = DateTime.Parse(tbDate.Text);
DateTime end = start.AddMonths(6);
DateTime today = DateTime.Today;
if (end >= today)
{
// Today is 6 months or more from the start date
}
else
{
// ...
}
Or alternatively - and not equivalently:
DateTime target = DateTime.Parse(tbDate.Text);
DateTime today = DateTime.Today;
DateTime sixMonthsAgo = today.AddMonths(-6);
if (sixMonthsAgo >= target)
{
// Six months ago today was the target date or later
}
else
{
// ...
}
Note that you should only evaluate DateTime.Today (or DateTime.Now etc) once per set of calculations - otherwise you could find it changes between evaluations.
Try with this
DateTime s = Convert.ToDateTime(tbDate.Text);
s = s.Date;
if (DateTime.Today.AddMonths(-6) == s) //if given date is equal to exactly 6 months past from today (change == to > if date has to be less 6 months)
{
lblResult.Text = "true"; //this doesn't work with the entered date above.
}
replace == with >= or <= according to your needs
I am creating a function that will set the date of an event, based on the current time.
I have an enumeration of events:
public enum EventTimings
{
Every12Hours, // 12pm and midnight
Weekly // sunday at midnight
}
public static DateTime CalculateEventTime(EventTimings eventTime)
{
DateTime time;
switch(eventTime)
{
case EventTimings.Every12Hours:
break;
}
return time;
}
So (Every12Hour event type) if the current time is 10am, then the eventdate will be the same day but at 12pm.
How should I write this?
I also have to make sure this works for December 31st and any other strange outlier date/time.
Is datetime the best for this scenerio?
If you want to be able to test anything, I would make the DateTime you are trying to "round" explicit, something like
public static DateTime RoundedDate(DateTime eventTime, EventTimings strategy)
{
switch (strategy)
case EventTimings.Weekly :
return WeeklyRounding(eventTime);
... etc ...
That way you can now write a specialized method for the 12-hour interval, the week interval, and test it for any input date possible, without depending on your computer clock.
You could also try something like this, although it breaks down if you want to do something monthly (because months each have a different number of days.) Also, while this simplified method will ensure a returned date at 12 and midnight, the weekly offset would be every 7 days from the starting day... not necessarily on Sundays. You could easily accomodate that behavior with a switch statement, though. The overloaded method also allows you some flexibility to provide a custom offset.
Also, to answer your question, yes I would use System.DateTime and System.TimeSpan. They handle determining whether a year or month has "rolled over" for you.
public enum EventTimings : int
{
Default = 12, // Default every 12 hours.
NoonAndMidnight = 12, // Every 12 hours.
Weekly = 168, // 168 hours in a week.
ThirtyDays = 720 // 720 hours in 30 days.
}
public DateTime CalculateDateTime(DateTime starting, EventTimings timing)
{
return CalculateDateTime(starting, TimeSpan.FromHours((int)timing));
}
public DateTime CalculateDateTime(DateTime starting, TimeSpan span)
{
DateTime baseTime = new DateTime(starting.Year, starting.Month, starting.Day, starting.Hour >= 12 ? 12 : 0, 0, 0);
return baseTime.Add(span);
}
I agree to keep it generic by making the reference date an input parameter instead of current datetime. However as you have asked about the logic for your eventTime values as well, this is how I would go about.
How should I write this?
For every12hours, check the hour property of the input date and check if it is less than 12. If so, then create a new TimeSpan for 12pm and add it to the datepart of the input date.
If not, add 1 day to the input date, create a TimeSpan for 12am and add it to the datepart of inputdate.
For weekly (Monday 12am), check the dayoftheweek of the inputdate and just add number of days to make it equal to the incoming Monday (Which is as simple as (8 - dayoftheweek)) and add a 12am TimeSpan to the date of the incoming Monday's date.
public enum EventTimings
{
Every12Hours, // 12pm and midnight
Weekly // sunday at midnight
}
public static DateTime CalculateEventTime(EventTimings eventTime, DateTime inputDate)
{
DateTime time = DateTime.Now;
switch (eventTime)
{
case EventTimings.Every12Hours:
time = inputDate.Hour > 12 ? inputDate.AddDays(1).Date + new TimeSpan(0, 0, 0) : inputDate.Date + new TimeSpan(12, 0, 0);
return time;
case EventTimings.Weekly:
int dayoftheweek = (int) inputDate.DayOfWeek;
time = inputDate.AddDays(8 - dayoftheweek).Date + new TimeSpan(0, 0, 0);
return time;
// other cases
}
}
Is datetime the best for this scenerio?
Yes. Your datetime calculations using DateTime and TimeSpan should take care of leap years, daylight savings or endofyear scenarios. Additionally you could try adding SpecifyKind to denote it is local time.
The algorithm I'd follow goes like this...
Put noon on the day of eventTime into a variable
Check if that variable is before eventTime
If it's not, add 12 hours to it
Return the variable
switch (strategy)
{
case EventTimings.Every12Hours:
//get noon for the event date
DateTime x = eventTime.Date.AddHours(12);
//check to see if x is after the eventTime
if (x < eventTime)
{
//if so, advance x by 12 hours to get midnight on the next day
x = x.AddHours(12);
}
return x;
break;
//other cases...
}