Position of a word/var in a list SAS

Question

This might be a rather simple question but I am new to SAS and am clueless even after researching on this in Google.

I have a macro variable as -

%let list = 12AUG2013 13AUG2013 15AUG2013 16AUG2014 09SEPT2014;

I need to get the following things -

a) Total words in list: In R this would be length(list). But in SAS, length counts each character. COUNTW does not work. Anyway I can do this?

b) Finding the ith word: If I need the 3rd element in this list, I would say list[3] in R. How can I do that in SAS?

c) Finding the position of an element: Suppose I need to know which position 16AUG2014 is at in the list variable, how can I get it?

Thanks for all the help!

Answer 1

The Code for position in list is

%let list_pos=%sysfunc(countw(%substr(&list,1,%index(&list,16AUG2014)+1)));  

Cheers

Answer 2

As you're asking about macro variables, it's a little different to using SAS data-step functions. Your questions provide a useful example of how they differ. Some data-step functions have macro function equivalents %SCAN, %SUBSTR etc. Others will require the use of %SYSFUNC, which allows most SAS datastep functions to be converted into macro functions.

So, referring to your example:

%let list = 12AUG2013 13AUG2013 15AUG2013 16AUG2014 09SEPT2014;

%let list_numwords = %sysfunc(countw(&list)); /* This example shows the use of SYSFUNC */
%let list_word3 = %scan(&list,3); /* These examples show the use of SCAN and INDEX, inbuilt macro functions*/
%let list_pos16AUG2014 = %index(&list,16AUG2014);

The code creates new macro variables that store the answers to your questions a,b and c* respectively.

* If you require the word number of 16AUG2014 (i.e. 4), then this is a little more difficult as I don't think there's a string function for this in SAS. It would involve using a combination of COUNT and %SUBSTR.