Would anyone have any ideas of how to best calculate the amount of days that intersect between two date ranges?
Here's a little method I wrote to calculate this.
private static int inclusiveDays(DateTime s1, DateTime e1, DateTime s2, DateTime e2)
{
// If they don't intersect return 0.
if (!(s1 <= e2 && e1 >= s2))
{
return 0;
}
// Take the highest start date and the lowest end date.
DateTime start = s1 > s2 ? s1 : s2;
DateTime end = e1 > e2 ? e2 : e1;
// Add one to the time range since its inclusive.
return (int)(end - start).TotalDays + 1;
}
Obtain a new range, defined by the later of the beginnings and the earlier of the ends, and determine the number of days since the beginning of the epoch for each day in that new range.
The difference is the number of days in the intersection. Accept only positive values.
Edited to take into account ranges instead of individual dates.
Here is an example from R. That might clarify the answer.
c_st = as.POSIXct("1996-10-14")
c_ed = as.POSIXct("1996-10-19")
d_st = as.POSIXct("1996-10-17")
d_ed = as.POSIXct("1999-10-22")
max(range(c_st,c_ed ))-min(range(d_st,d_ed) ) >= 0 & min(range(c_st,c_ed )) < max(range(d_st,d_ed) )
True would indicate that they intersect, False otherwise.
[r]
If I understand your question, you're asking for the number of days that overlap two date ranges, such as:
Range 1 = 2010-1-1 to 2010-2-1
Range 2 = 2010-1-5 to 2010-2-5
in this example the number of intersecting days would be 28 days.
Here is a code sample for that example
DateTime rs1 = new DateTime(2010, 1, 1);
DateTime re1 = new DateTime(2010, 2, 1);
DateTime rs2 = new DateTime(2010, 1, 5);
DateTime re2 = new DateTime(2010, 2, 5);
TimeSpan d = new TimeSpan(Math.Max(Math.Min(re1.Ticks, re2.Ticks) - Math.Max(rs1.Ticks, rs2.Ticks) + TimeSpan.TicksPerDay, 0));
The question asks between two date Ranges not two Dates. (Edited in response to comments)
So if you have 2 Date Ranges (r1s,r1e), you need to determine which starts first, Is there overlap, and what is the overlap.
double overlap(DateTime r1s, DateTime r1e, DateTime r2s, DateTime r1e){
DateTime t1s,t1e,t2s,t2e;
if (rs1<rs2) //Determine which range starts first
{
t1s = r1s;
t1e = r1e;
t2s = r2s;
t2e = r2e;
}
else
}
t1s = r2s;
t1e = r2e;
t2s = r1s;
t2e = r1e;
}
if (t1e<t2s) //No Overlap
{
return -1;
}
if (t1e<t2e) //Partial Overlap
}
TimeSpan diff = new TimeSpan(t1e.Ticks - t2s.Ticks);
{
else //Range 2 totally withing Range 1
}
TimeSpan diff = new TimeSpan(t2e.Ticks - t2s.Ticks);
{
double daysDiff = diff.TotalDays;
return daysDiff;
}
Related
I have a datasource that returns dates and I have to find where the months falls within the month and day range buckets. The months and day range buckets are predefined so I put it in a Dictionary (not sure if that is even a good idea). I am using linq to find the min and Max dates and extracting the month from them. I need to find month from the dictionary where that month extracted falls within the range. For Example
Dictionary<int, int> MonthDayBuckets = new Dictionary<int, int>() { { 3,31 }, { 6,30 }, { 9,30 }, { 12,31 } };
var MinyDate = _dataSource.Min(x => x.values[0]);
var MaxDate = _dataSource.Max(x => x.values[0]);
var startMonth = Convert.ToDateTime(MinyDate).ToString("MM");
var endMonth = Convert.ToDateTime(MaxDate).ToString("MM");
Say startmonth return Jan so I want to be able to go to the dictionary and return only march (03.31) and if I get 10 for the Max (October) I am trying to return (12,31) December
If my understanding is correct, your MonthDayBuckets variable is meant to represent date ranges:
3/31 - 6/30
6/30 - 9/30
9/30 - 12/31
12/31 - 3/31
...and given a month, you're wanting to see what the end date is of the interval that the first of that month falls between? Like you gave the example of October returning 12/31.
This problem can be simplified since you'll get the same result saying "what's the next occurring date after this given date?" The next occurring date for 10/01 would be 12/31. So here's how you could rearrange your data:
var availableDates = new List<string> { "03/31", "06/30", "09/30", "12/31" };
Now you'll be able to find a match by finding the index of the first one that's greater than your given date. Note how I made the month/day combos lexicographical orderable.
var startMonth = Convert.ToDateTime(MinyDate).ToString("MM");
var startDate = startMonth + "/01";
var endMonth = Convert.ToDateTime(MaxDate).ToString("MM");
var endDate = endMonth + "/01";
// Wrap around to the first date if this falls after the end
var nextStartDate = availableDates.FirstOrDefault(d => d.CompareTo(startDate) >= 1) ?? availableDates[0];
var nextEndDate = availableDates.FirstOrDefault(d => d.CompareTo(endDate) >= 1) ?? availableDates[0];
You could use Linq for the purpose. For example,
var nearestKey = MonthDayBuckets.Keys.Where(x => x >= endMonth.Month).Min();
var nearestDate = new DateTime(DateTime.Now.Year,nearestKey,MonthDayBuckets[nearestKey]); // or whatever the year it needs to be represent
Though above query would get you the result, I would suggest you define a structure to store the Range itself, rather than using Dictionary
For example,
public class Range
{
public MonthDate StartRange{get;set;}
public MonthDate EndRange{get;set;}
public Range(MonthDate startRange,MonthDate endRange)
{
StartRange = startRange;
EndRange = endRange;
}
}
public class MonthDate
{
public MonthDate(int month,int date)
{
Month = month;
Date = date;
}
public int Month{get;set;}
public int Date{get;set;}
//Depending on if your Ranges are inclusive or not,you need to decide how to compare
public static bool operator >=(MonthDate source, MonthDate comparer)
{
return source.Month>= comparer.Month && source.Date>=comparer.Date;
}
public static bool operator <=(MonthDate source, MonthDate comparer)
{
return source.Month<= comparer.Month && source.Date<=comparer.Date;
}
}
Now you could define ranges as
var dateRanges = new Range[]
{
new Range(new MonthDate(12,31),new MonthDate(3,31)),
new Range(new MonthDate(3,31),new MonthDate(6,30)),
new Range(new MonthDate(6,30),new MonthDate(12,31)),
};
var result = dateRanges.First(x=>x.StartRange <= new MonthDate(endMonth.Month,endMonth.Day) && x.EndRange >= new MonthDate(endMonth.Month,endMonth.Day));
I have regular list of date ranges with specific value:
14.09.2012 - 31.12.2015 = 8.25
01.01.2016 - 13.06.2016 = 11.00
14.06.2016 - 18.09.2016 = 10.50
19.09.2016 - 26.03.2017 = 10.00
27.03.2017 - 01.05.2017 = 9.75
02.05.2017 - 18.06.2017 = 9.25
19.06.2017 - 17.09.2017 = 9.00
18.09.2017 - 29.10.2017 = 8.50
30.10.2017 - 17.12.2017 = 8.25
18.12.2017 - 11.02.2018 = 7.75
12.02.2018 - 25.03.2018 = 7.50
26.03.2018 - 16.09.2018 = 7.25
17.09.2018 - NOW = 7.50
I am looking for a method that divide one input data range into above data ranges taking into account coefficient value.
For example, if I have input date range 01.01.2016 - 09.02.2016, I need to get one output date range and coefficient:
01.01.2016 - 13.06.2016 = 11.00
But if I have input date range 01.01.2016 - 29.04.2017, I need to get following ranges and coefficients:
14.09.2012 - 31.12.2015 = 8.25
01.01.2016 - 13.06.2016 = 11.00
14.06.2016 - 18.09.2016 = 10.50
19.09.2016 - 26.03.2017 = 10.00
27.03.2017 - 01.05.2017 = 9.75
Class for output data:
public class OutputItem
{
public OutputItem()
{
}
public DateTime Start { get; set; } = new DateTime();
public DateTime End { get; set; } = new DateTime();
public double Coeff { get; set; } = 0;
}
Method that I try to get output data
private List<OutputItem> GetOutput(DateTime start, DateTime end, List<OutputItem> specificRanges)
{
List<OutputItem> periods = new List<OutputItem>();
foreach (OutputItem sr in specificRanges)
{
if (start >= sr.Start && sr.End <= end)
{
periods.Add(new OutputItem { Start = sr.Start, End = sr.End, Coeff = sr.Coeff });
}
}
return periods;
}
So I'm going to go out on a limb here and assume that in your second example the start date should have been before 01-01-2016 - because if I understand the question, you are looking to return all the ranges that overlap the start to end time you are passing to the method.
If that is indeed the case, you are close - but your condition is wrong.
The way to test if two ranges overlap is to check if one starts before the other ends and vice versa, as you can see in the wiki of the overlap tag:
Two or more elements overlap when they partially or totally cover one another.
The way to find if the elements overlap or not is to test if one elements begins before the second one ends, while the second one begins before the first one ends.
So your method should be:
private List<OutputItem> GetOutput(DateTime start, DateTime end, List<OutputItem> specificRanges)
{
List<OutputItem> periods = new List<OutputItem>();
foreach (OutputItem sr in specificRanges)
{
if (start >= sr.End && sr.Start <= end)
{
periods.Add(new OutputItem { Start = sr.Start, End = sr.End, Coeff = sr.Coeff });
}
}
return periods;
}
Below is my code. I am only getting the difference between two dates, but I want the name of that month which comes between the from and to dates.
public static int GetMonthsBetween(DateTime from, DateTime to)
{
if (from > to) return GetMonthsBetween(to, from);
var monthDiff = Math.Abs((to.Year * 12 + (to.Month - 1)) - (from.Year * 12 + (from.Month - 1)));
if (from.AddMonths(monthDiff) > to || to.Day < from.Day)
{
return monthDiff - 1;
}
else
{
return monthDiff;
}
}
Based on your code you could substract the month difference from the "to" DateTime to get DateTime difference from your input.
public static List<DateTime> GetMonthsBetween(DateTime from, DateTime to)
{
if (from > to) return GetMonthsBetween(to, from);
var monthDiff = Math.Abs((to.Year * 12 + (to.Month - 1)) - (from.Year * 12 + (from.Month - 1)));
if (from.AddMonths(monthDiff) > to || to.Day < from.Day)
{
monthDiff -= 1;
}
List<DateTime> results = new List<DateTime>();
for (int i = monthDiff; i >= 1; i--)
{
results.Add(to.AddMonths(-i));
}
return results;
}
To get the name of the month just format the DateTime to "MMM".
var dts = GetMonthsBetween(DateTime.Today, DateTime.Today.AddMonths(5));
foreach (var dateTime in dts)
{
Console.WriteLine(dateTime.ToString("MMM"));
}
If you want the names of all months between two dates, use something like this:
var d1 = new DateTime(2015,6,1);
var d2 = new DateTime(2015,9,1);
var monthlist = new List<string>();
string format = d1.Year == d2.Year ? "MMMM" : "MMMM yyyy";
for (var d = d1; d <= d2; d = d.AddMonths(1))
{
monthlist.Add(d.ToString(format));
}
The full list is now in monthlist - you will want to return that from your method.
Assuming you're using Java and JodaTime there are several flaws in your code.
You cant use from > to to evaluate if a date is after an other. Use from.isAfter(to) instead.
JodaTime already supplies a method to calculate the amount of whole months between two given Dates Months.monthsBetween(start,end).
With the calculated month difference you can instantiate a new DateTime object that holds a date in your desired month and output its name via yourNewDateTimeObject.month().getAsText().
edit: Just found out you're using C# so ignore my text above this. Below here I will try to answer your question in C#.
Why dont you just subtract the from from the to date and obtain your difference?
The resulting TimeSpan can be used to determine the amount of whole months between your two given dates.
To obtain the resulting month name you could use yourDateTime.ToString("MMMM");
is it possible to have something that can compare two dates in this format..
example today "Sep 30, 2013" and one week ago "Sep 22, 2013"
if its within this range say "good" if older then say "not good"
how can I make this in C# or vb.net
If difference between dates is smaller than 7 days, it will print "good" otherwise "Not good"
var ok = (firstDate-secondDate).TotalDays < 7? "good": "Not good";
Console.WriteLine(ok);
TotalDays is double so you can check if differnce is in full days, use Days if you want completed days difference as int
Read more about TimeSpan and it's properties.
if(date1 >= Convert.ToDateTime("Sep 22, 2013") && date1 <= Convert.ToDateTime("Sep 30, 2013"))
{
good
}
else
{
bad
}
You can use this generic Range class for checking some comparable value (like DateTime) falls into range:
public class Range<T>
where T : IComparable
{
public Range(T from, T to)
{
if (from.CompareTo(to) > 0)
throw new ArgumentException("From should not be greater than To");
From = from;
To = to;
}
public T From { get; private set; }
public T To { get; private set; }
public bool Contains(T value)
{
return value.CompareTo(From) >= 0 && value.CompareTo(To) <= 0;
}
// other methods like Intersects etc
}
Usage:
var today = DateTime.Today;
var range = new Range<DateTime>(today.AddDays(-7), today);
DateTime date = new DateTime(2013, 9, 25);
if (range.Contains(date))
// say good
thanks to all users who helped me here.. this is the final code that I am using..
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim fileDate As Date = Convert.ToDateTime("Sep 25, 2013")
Dim rightNow As Date = Convert.ToDateTime(Date.Now.ToString("MMM dd, yyyy"))
Dim lastWeek = rightNow.AddDays(-7)
If rightNow >= fileDate And lastWeek <= fileDate Then
Debug.Print("its new")
Else
Debug.Print("too old")
End If
End Sub
I have a what seems like simple date issue and I just can't wrap my head around trying to get it efficiently... I basically need to get the previous months date for a specific day.
For example: If today is the 3rd Thursday of the month, I want to get the 3rd Thursday's date of last month. Its important that its based of the number of the day...ie: First Monday, 4th Friday, 2nd Wednesday, etc.
What's the best way to get this done?
BTW...If there is not an equivalent previous months day that is fine. I can handle that. Also, currently I am counting the number or days ("Mondays", "Tuesdays", etc) manually to figure this out. I was just hoping there is a more elegant way to do it.
Here's what I would do:
static DateTime? GetLastMonthSameNthDayOfWeek(DateTime date)
{
int nth = (date.Day-1) / 7; // returns 0 if 1st, 1 if 2nd...
var prevMonthDay = date.AddMonths(-1);
// find the first date of month having the same day of week
var d = new DateTime(prevMonthDay.Year, prevMonthDay.Month, 1);
while(d.Day <= 7)
{
if (d.DayOfWeek == date.DayOfWeek)
break;
d = d.AddDays(1);
}
// go to nth day of week
d = d.AddDays(7 * nth);
// if we have passed the current month, there's no nth day of week
if (d.Month != prevMonthDay.Month)
return null;
return d;
}
Usage example:
// 3rd wednesday of August 2012
var a = new DateTime(2012, 8, 15);
var aPrev = GetLastMonthSameNthDayOfWeek(a);
// aPrev = July 18th 2012 (i.e. the 3rd wednesday of July 2012)
// 5th wednesday of August 2012
var b = new DateTime(2012, 8, 15);
var bPrev = GetLastMonthSameNthDayOfWeek(b);
// bPrev = null, because there's no 5th wednesday of July 2012
N.B. :
getting the ordinal position of the day of week inside a month is really easy:
int nth = ((date.Day-1) / 7) + 1; // 1 -> 1st, 2 -> 2nd, 3 -> 3rd ...
As I couldn't find a built-in way, I've written this simple extension method for DateTime, check it out:
public static class DateTimeExtension
{
public static DateTime GetPositionalDate(this DateTime BaseDate, DayOfWeek WeekDay, int position)
{
if (position < 1)
{
throw new Exception("Invalid position");
}
else
{
DateTime ReturnDate = new DateTime(BaseDate.Year, BaseDate.Month, BaseDate.Day);
int PositionControl = 1;
bool FoundDate = false;
while(ReturnDate.DayOfWeek != WeekDay)
{
ReturnDate = ReturnDate.AddDays(1);
}
while (!FoundDate && PositionControl <= position)
{
PositionControl++;
if (PositionControl == position)
{
FoundDate = true;
}
else
{
ReturnDate = ReturnDate.AddDays(7);
}
}
if (FoundDate)
{
return ReturnDate;
}
else
{
throw new Exception("Date not found");
}
}
}
}
Usage:
DateTime lastMonth = DateTime.Now.GetPositionalDate(DayOfWeek.Sunday, 2);
Regards
There is no, by default, a way that .Net understand this specific logic for dates. So using the following, you can get what you're looking for:
var now = DateTime.Now.Date;
Use DateTime.AddMonth(-1) to get last month.
Use DateTime.AddDays(now.Days * -1 + 1) to get the first of the month.
Use DateTime.DayOfWeek to determine the day and subtract or add days as necessary
Ok, what you can do is determine the day of the week of the first day of the month last month, take the difference between the day of the week you want and that day of the week, then add 7 * the weeks you want (less one week)...
// Let's get the 3rd Friday of last month:
// get starting date
DateTime date = new DateTime();
// get first day of last month
DateTime firstOfLastMonth = date.AddMonths(-1).AddDays(-1 * (date.Day + 1));
// subtract out the day of the week (get the previous Sunday, even if it is last month)
DateTime justBeforeMonth = firstOfLastMonth.AddDays((int)firstOfLastMonth.DayOfWeek);
// Add in the DayOfWeek number we are looking for
DateTime firstFridayOfMonth = justBeforeMonth.AddDays(DayOfWeek.Friday);
// if we are still in last month, add a week to get into this month
if (firstFridayOfMonth.Month != date.AddMonth(-1).Month) { firstFridayOfMonth.AddDays(7); }
// add in 2 weeks to get the third week of the month
DateTime thirdFridayOfMonth = firstFridayOfMonth.AddDays(14);
Here's the solution I came up with. If the day doesn't exist (e.g. 8th Saturday), GetDate() will return null:
{
DateTime lastMonth = new DateTime(DateTime.Now.Year, DateTime.Now.Month, 1).AddMonths(-1);
DateTime? date = GetDate(lastMonth.Month, lastMonth.Year, DayOfWeek.Thursday, 2);
}
private static DateTime? GetDate(int month, int year, DayOfWeek dayOfWeek, int which)
{
DateTime firstOfMonth = new DateTime(year, month, 1);
DateTime date;
for (date = firstOfMonth; date.DayOfWeek != dayOfWeek; date = date.AddDays(1))
;
date = date.AddDays(7 * (which - 1));
return date.Month == month && date.Year == year ? (DateTime?)date : null;
}