Converting Date Values in SAS

[sasshelp]

I am trying to create a sas job that assigns a week number to a group of 7 dates. So for example, March 1 - March 7 is Week 1, March 8 through March 15, is Week 2...etc.

I'd originally thought an 2-dim array would resolve this problem, but have given up on that idea.

The other option was to designate a system date value as Start date and increment Start date by a certain number. If the variable ddate is between the min and max start dates then a week number would assigned. Example here:

&start=17112; /* Denotes sys date value of 11/7/06 */
&end = 17139; /* Denotes sys date value of 12/4/06 */

data test;
input @1 ddate PD5.0; /*variable ddate is yyddmm. format*/

week=0;
start=&start;

if start <= ddate <= (start +6) then week=1;
if (start+7) <= date <= (start+13) then week=2;
IF (START+14) <= DDATE<= (START+20) THEN WEEK=3;
IF (START+21) <= DDATE<= (START+27) THEN WEEK=4;
IF (START+28) <= DDATE<= (START+30) AND DDATE<=END THEN WEEK=5;
END;

format ddate yymmdd10.;
run;

The problem that occurs is that SAS does not seem to be able to recognize DDate as having a system date value that falls between start point 1 and start point 2. Therefore, when I run a proc freq; tables week;, I get no returned values. The data infile has ddates that are between the start and end dates.


Note: This program is set up in a mainframe environment (I am not using PC SAS).

 

[sarav1981]

Hi Sasshelp,

I did not get your question completely, but I will have a jab at it anyway.

If you want the week to be computed as the week of the year, try using the WEEK function in SAS.

The syntax would be: week(<sas_date>,<modifier>). You can look up more on this function using SAS help and determine the modifier that you need. This function returns the week number in a year.

If you want to determine the count of time intervals between two date intervals (which I think you want to do), use the INTCK function instead of adding 7 to the start date.

For example, intck('week','12MAR2007'd,'18MAR2007'd) would return 1 week.

Hope this helps!

Sarav

 

[klaz2002]

sashelp,
I don't understand why you do not use the following sas statement:

week = int((ddate - start) / 7)+1;

If you want to have all dates after the December 4, 2006 to be lumped together with week 5 values, use a reset statement. Like IF WEEK > 5 THEN WEEK = 5;

Hope that this helps you,
Klaz