topic Re: Getting residual time of date differences in a different unit in SAS Programming

Getting residual time of date differences in a different unit

cbt2119 — Thu, 17 Aug 2017 14:28:46 GMT

Hi SAS Community,

I am trying to get a difference in between two dates, a start date and an end date, in weeks and the residual days. Is there a sas formula for this that wont require me to do a lot of work-around? I'm finding a lot of resources for computing date difference variables in one unit or one unit plus time, but not two different units (weeks + days).

For example:

Start date: 03-Aug-2006

End date: 11-Oct-2006

Calculated result I want: 9 weeks, 6 days.

Thanks!

Cara

Re: Getting residual time of date differences in a different unit

Shmuel — Thu, 17 Aug 2017 14:37:24 GMT

Try -

weeks = intck('week', start_date, end_date);

res = end_date - start_date - weeks*7;

result = left(weeks) || ' Weeks, ' || left(res) || ' Days';

Re: Getting residual time of date differences in a different unit

Astounding — Thu, 17 Aug 2017 14:50:59 GMT

It depends on your concept of "a lot of workaround". You could try:

data want;

set have;

n_days = end_date - start_date;

n_weeks = int(n_days / 7);

n_days = mod(n_days, 7);

final_variable = catx(' ', n_weeks, 'weeks,', n_days, 'days');

run;

As a general rule of thumb, I recommend avoiding INTCK unless you are certain of what it does, and certain that it does what you want. Here is a test program to illustrate some of the intricacies:

data _null_;

start_date = '11Aug2017'd;

end_date = '14Aug2017'd;

weeks = intck('week', start_date, end_date);

put weeks=;

start_date = '07Aug2017'd;

end_date = '19Aug2017'd;

weeks = intck('week', start_date, end_date);

put weeks=;

start_date = '08Aug2017'd;

end_date = '20Aug2017'd;

weeks = intck('week', start_date, end_date);

put weeks=;

run;

Re: Getting residual time of date differences in a different unit

PeterClemmensen — Thu, 17 Aug 2017 14:40:43 GMT

@Shmuel wouldn't you have to subtract 1 from weeks? 🙂

Re: Getting residual time of date differences in a different unit

cbt2119 — Thu, 17 Aug 2017 14:47:30 GMT

This works well - thanks for posting. It's still a bit clumsy (was hoping sas had a function similar to Excel's Datedif function) but works well. Thanks!

Re: Getting residual time of date differences in a different unit

Shmuel — Thu, 17 Aug 2017 14:47:55 GMT

@PeterClemmensen -

weeks = intck('week', start_date, end_date);

result into 1 for dates 01JAN2017 to 09JAN2017, which means it calculate whole weeks of 7 days.

Re: Getting residual time of date differences in a different unit

PeterClemmensen — Thu, 17 Aug 2017 14:57:41 GMT

Ah yes, I see 🙂