topic Creating date from existing date field in SAS Programming

Creating date from existing date field

Sas_noob25 — Tue, 20 Sep 2022 15:57:29 GMT

I am attempting to create a new date field in a dataset based on an existing date field.

I'm looking to create a new field 'end_date' that is 60 days after various dates in a dataset in column 'existing_date'.

data want;

set have;

format end_date date9.;

end_date = intck('days',existing_date,60);

Below are my results.

Thank you in advance!

Re: Creating date from existing date field

FreelanceReinh — Tue, 20 Sep 2022 16:08:01 GMT

Hello @Sas_noob25,

Replace intck with intnx and it should work.

Or simply write

end_date = existing_date+60;

Re: Creating date from existing date field

Reeza — Tue, 20 Sep 2022 16:12:08 GMT

INTCK calculates intervals between two dates.
INTNX increments dates.

end_date = intnx('day', existing_date, 60);
end_date = existing_date + 60;

Re: Creating date from existing date field

Tom — Tue, 20 Sep 2022 16:14:47 GMT

Your code is counting how many day intervals there are between the start date and day number 60 (which is the first day of March in the year 1960) . That will be a very large negative number. Since day zero is January first of 1960 you can see why you ended up with dates that are in the 19th century.

If you want to add 60 days to the number of days that are stored in EXISTING_DATE then addition is the simplest way.

end_date = existing_date+60;
format end_date date9.;

If you want to add a multiple of some other interval that is NOT the unit that the value is already stored in then you could use the INTNX() function instead of the INTCK() function. For example if you wanted to add two months you could use the MONTH interval.

end_date = intnx('month',existing_date,2,'s');

Re: Creating date from existing date field

ballardw — Tue, 20 Sep 2022 17:07:22 GMT

Possibly a silly question. Is that 60 days used as a substitute for "two months"? As in what is the expected result of 60 days after 25Mar2022?

If you want 25May2022, the same day of the two months later, then you would use Intnx('month',date,2,'s');

Re: Creating date from existing date field

Sas_noob25 — Tue, 20 Sep 2022 17:25:40 GMT

Thank you, both of these worked out for me. in the intnx function, what is the 's' doing at the end?

Re: Creating date from existing date field

Sas_noob25 — Tue, 20 Sep 2022 17:26:09 GMT

Thank you! Both of these options worked.

Re: Creating date from existing date field

Tom — Tue, 20 Sep 2022 18:10:02 GMT

@Sas_noob25 wrote:

Thank you, both of these worked out for me. in the intnx function, what is the 's' doing at the end?

Read the documentation.

'alignment'

controls the position of SAS dates within the interval. You must enclose alignment in quotation marks. Alignment can be one of these values: BEGINNING, MIDDLE, END, and SAME. SAME specifies that the date that is returned has the same alignment as the input date. For more information, see SAS DS2 Language Reference.

controls the position of SAS dates within the interval. You must enclose alignment in quotation marks. Alignment can be one of these values:

BEGINNING

specifies that the returned date or datetime value is aligned to the beginning of the interval.

Alias	B

MIDDLE

specifies that the returned date or datetime value is aligned to the midpoint of the interval, which is the average of the beginning and ending alignment values.

Alias	M

END

specifies that the returned date or datetime value is aligned to the end of the interval.

Alias	E

SAME

specifies that the date that is returned has the same alignment as the input date.

Aliases	S
Aliases	SAMEDAY
See	SAME Alignment

Default	BEGINNING
Data type	CHAR, NCHAR, NVARCHAR, VARCHAR
See	Aligning SAS Date Output within Its Intervals