How to get the integer value of day of week

Question

How do I get the day of a week in integer format? I know ToString will return only a string.

DateTime ClockInfoFromSystem = DateTime.Now;
int day1;
string day2;
day1= ClockInfoFromSystem.DayOfWeek.ToString(); /// it is not working
day2= ClockInfoFromSystem.DayOfWeek.ToString(); /// it gives me string

@Joe, I was unable to reformat his code for placing his code in code block, why is that? — uday, Feb 08 '12 at 18:18
You're calling `ToString()` so why would you expect anything but a string? — Brian Rasmussen, Feb 08 '12 at 18:21
@Dave, I had to separate it a line from the text of the question, or else it just indented the code... — Joe, Feb 08 '12 at 18:44
cool! I was trying to make his code into codeblock & it dint allow me to do. — uday, Feb 08 '12 at 18:45

score 207 · Accepted Answer · answered Feb 08 '12 at 18:17

207

Use

day1 = (int)ClockInfoFromSystem.DayOfWeek;

answered Feb 08 '12 at 18:17

Joe

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it will return 0 for monday and so on ? – akshaykumar6 Feb 08 '12 at 18:23
12

@developer Sunday is 0. http://msdn.microsoft.com/en-us/library/system.dayofweek.aspx – Roy Goode Feb 08 '12 at 18:24
50

If you want monday to be 0, just shift the days: `day1 = (int)(ClockInfoFromSystem.DayOfWeek + 6) % 7` – Kevin Gosse Feb 08 '12 at 18:38
4

If you want to do it faster, take a look to this: http://stackoverflow.com/a/22278311/3315914 – rpax Mar 10 '14 at 13:16

score 106 · Answer 2 · edited Jan 22 '17 at 21:32

106

int day = (int)DateTime.Now.DayOfWeek;

First day of the week: Sunday (with a value of zero)

edited Jan 22 '17 at 21:32

peroija

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answered Feb 08 '12 at 20:42

score 81 · Answer 3 · answered Dec 30 '13 at 02:49

81

If you want to set first day of the week to Monday with integer value 1 and Sunday with integer value 7

int day = ((int)DateTime.Now.DayOfWeek == 0) ? 7 : (int)DateTime.Now.DayOfWeek;

answered Dec 30 '13 at 02:49

Martin Sansone - MiOEE

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Up-voted as all sane people would want this. ISO 8601 is quite clear on the point. Monday is day 1, Sunday is day 7. – Morvael Aug 18 '16 at 10:30
Didn't release the DayOfWeek property would return zero on sunday. Almost introduced a bug by implementing the top voted answer. Thanks! – brz Jul 18 '19 at 07:32

score 6 · Answer 4 · edited Aug 18 '16 at 13:22

6

Try this. It will work just fine:

int week = Convert.ToInt32(currentDateTime.DayOfWeek);

edited Aug 18 '16 at 13:22

Jarosław Kończak

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answered Sep 25 '14 at 10:25

RaviKant Hudda

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score 6 · Answer 5 · answered Dec 24 '14 at 09:41

6

The correct way to get the integer value of an Enum such as DayOfWeek as a string is:

DayOfWeek.ToString("d")

answered Dec 24 '14 at 09:41

Rob Sedgwick

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This will return a `string`, not an `int`. – Danny Beckett May 11 '15 at 20:02
This is day of month not day of week – Fritz Apr 25 '18 at 11:35
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@Fritz no it's not, its an enum integer "as a string" as I said. You are getting confused with date formatting which this is not. – Rob Sedgwick Mar 06 '19 at 23:02

score 6 · Answer 6 · answered Feb 08 '12 at 18:17

6

day1= (int)ClockInfoFromSystem.DayOfWeek;

answered Feb 08 '12 at 18:17

FiveTools

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@JustinSatyr - FiveTools was clearly just giving an example. It is not his fault the author was attempting to set a String value to an integer variable. – Security Hound Feb 08 '12 at 18:23
@Ramhound: I didn't downvote and I wasn't criticizing. I thought he misread the code. And apparently I was correct by the fact that he corrected his code. – Devin Burke Feb 08 '12 at 18:27

Ruslan Hayduk · Answer 7 · 2018-02-04T00:52:05.803

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Another way to get Monday with integer value 1 and Sunday with integer value 7

int day = ((int)DateTime.Now.DayOfWeek + 6) % 7 + 1;

edited Feb 04 '18 at 00:52

answered Feb 04 '18 at 00:44

Ruslan Hayduk

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score 2 · Answer 8 · answered Aug 19 '20 at 17:02

The correct answer, is indeed the correct answer to get the int value.

But, if you're just checking to make sure it's Sunday for example... Consider using the following code, instead of casting to an int. This provides much more readability.

if (yourDateTimeObject.DayOfWeek == DayOfWeek.Sunday)
{
    // You can easily see you're checking for sunday, and not just "0"
}

score 0 · Answer 9 · answered Mar 11 '14 at 21:26

0

DateTime currentDateTime = DateTime.Now;
int week = (int) currentDateTime.DayOfWeek;

answered Mar 11 '14 at 21:26

Michael Murphy

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score 0 · Answer 10 · answered Sep 13 '21 at 21:42

Readability counts.

If you need an integer:

int day1 = (int)ClockInfoFromSystem.DayOfWeek;

If you need a string of the weekday integer:

string daystr = $"{(int)ClockInfoFromSystem.DayOfWeek}"; // Unambiguous string of int.

Do not use the recommended ToString conversion, because the majority of programmers are going to have to look it up to make sure that it's a string of the integer and not day of month. Really Microsoft?

string daystr = ClockInfoFromSystem.DayOfWeek.ToString("d"); // Whaa? Horrible! Don't do this.

To change to start of week, add the number of days from Sunday mod 7. Count backwards from Sunday to get the number of days, e.g. 1 back from Sunday is Saturday, 2 back from Sunday is Friday, etc.

int satStart = (int)(ClockInfoFromSystem.DayOfWeek + 1) % 7; // Saturday start
int monStart = (int)(ClockInfoFromSystem.DayOfWeek + 6) % 7; // Monday start

How to get the integer value of day of week

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