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Posted 9 Nov 2011

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# Find the count of a weekday between two dates without iterating/looping

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11 Nov 2011CPOL
Single line in Linq This gets you the number of weekdays, i.e., Monday to Friday between given two dates.[VB]Dim dt1 As New Date(2011, 1, 1)Dim dt2 As New Date(2011, 1, 15)Dim days As Integer = (From d As Date In _ (Enumerable.Range(0, 1 +...
Single line in Linq

This gets you the number of weekdays, i.e., Monday to Friday between given two dates.
[VB]
VB
```Dim dt1 As New Date(2011, 1, 1)
Dim dt2 As New Date(2011, 1, 15)
Dim days As Integer = (From d As Date In _
(Enumerable.Range(0, 1 + dt2.Subtract(dt1).Days).Select(Function(offset) dt1.AddDays(offset)).ToArray()) _
Where d.DayOfWeek >= DayOfWeek.Monday And d.DayOfWeek <= DayOfWeek.Friday Select 1).Sum```

[C#]
C#
```DateTime dt1 = new DateTime(2011, 1, 1);
DateTime dt2 = new DateTime(2011, 1, 15);
int days = (from d in (Enumerable.Range(0, 1 + dt2.Subtract(dt1).Days).Select(offset => dt1.AddDays(offset)).ToArray())where d.DayOfWeek >= DayOfWeek.Monday & d.DayOfWeek <= DayOfWeek.Friday1).Sum;```

You can easily modify it to get the count of a particular day as,
[VB]
VB
```Dim dt1 As New Date(2011, 1, 1)
Dim dt2 As New Date(2011, 1, 15)
Dim days As Integer = (From d As Date In _
(Enumerable.Range(0, 1 + dt2.Subtract(dt1).Days).Select(Function(offset) dt1.AddDays(offset)).ToArray()) _
Where d.DayOfWeek = DayOfWeek.Monday Select 1).Sum```

[C#]
C#
```DateTime dt1 = new DateTime(2011, 1, 1);
DateTime dt2 = new DateTime(2011, 1, 15);
int days = (from d in (Enumerable.Range(0, 1 + dt2.Subtract(dt1).Days).Select(offset => dt1.AddDays(offset)).ToArray())where d.DayOfWeek == DayOfWeek.Monday).Sum;```

See here, `Enumerable.Range` gets you the array of dates between given dates. You can apply your conditions and get different results using Linq on it.

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 First Prev Next
 Reason for my vote of 1 This iterates, which is clearly to b... AspDotNetDev11-Nov-11 6:50 AspDotNetDev 11-Nov-11 6:50
 Re: Sorry for those wrong variable names. Corrected it. About it... Prerak Patel11-Nov-11 16:19 Prerak Patel 11-Nov-11 16:19
 Why did you provide an alternate using VB when the original ... #realJSOP10-Nov-11 2:18 #realJSOP 10-Nov-11 2:18
 Re: As I am basically a VB developer, I just made it and posted.... Prerak Patel10-Nov-11 3:27 Prerak Patel 10-Nov-11 3:27
 Dont you think LINQ is internally again a loop though with m... zenwalker19859-Nov-11 18:58 zenwalker1985 9-Nov-11 18:58
 Re: That's good example of maths in code, still, with this code ... Prerak Patel9-Nov-11 20:08 Prerak Patel 9-Nov-11 20:08
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