topic Formatting date variables in SAS Programming

Formatting date variables

GAL1986 — Thu, 08 Oct 2020 14:53:24 GMT

I am trying to create a unique ID that is a combination of an ID variable and a date.

In both datasets I have an ID variable which is a numeric variable with a length of 8 and format Best12. In one dataset I have delivery_date which is length 8, format MMDDYY10. and informat date9. In the other I have new_delivery_date which has the same characteristics.

The code I am using is

ID2=put(ID, 8.);

del_date2=put(delivery_date, 9.);

Del_ID = strip(ID2)||strip(del_date2);

And

ID2=put(ID, 8.);

del_date2=put(new_del_date, 9.);

Del_ID = strip(ID2)||strip(del_date2);

Here is an example of the del_ID for one patient in both datasets. Do you have any idea why the Del_IDs would not match in the datasets if the variables are all formatted the same way?

Dataset1:

ID 1001958 Del_ID 100195819038 new_del_date 02/15/2012

Dataset 2:

ID 1001958 Del_ID 100195819039 new_del_date 02/15/2012

Why does one Del_ID end in 8 and the other in 9 if the dates are formated the same way?

Re: Formatting date variables

Tom — Thu, 08 Oct 2020 15:03:23 GMT

SAS stores dates as the number of days. All numeric variables in SAS are floating point values. The date formats (like MMDDYY , DDMMYY, YYMMDD, DATE, etc) will only use the integer part of the value.

But 9. format you used to convert the number of days to an digit string will round instead.

Example:

1    data test;
2      today=today()+0.6;
3      put today= +1 today date9. +1 today 9. ;
4    run;

today=22196.6  08OCT2020     22197

If the goal is to make a string of digits that represents ID and DELIVERY_DATE then you should use leading zeros in the ID value to force it to always use the same number of digits. To represent dates in strings use Y-M-D order so that the strings will sort properly.

Like this:

length DEL_ID $16;
DEL_ID = put(id,Z8.) || put(delivery_date,yymmdd8.);

Re: Formatting date variables

GAL1986 — Thu, 08 Oct 2020 15:28:13 GMT

Thank you! I will try this today!