SAS simplify the contents of a variable - string

Question

In SAS, I've a variable V containing the following value
V=1996199619961996200120012001
I'ld like to create these 2 variables
V1=19962001 (= different modalities)
V2=42 (= the first modality appears 4 times and the second one appears 2 times)
Any idea ?
Thanks for your help.
Luc

Answer 1

For your first question (if I understand the pattern correctly), you could extract the first four characters and the last four characters:
a = substr(variable, 1,4)
b = substrn(variable,max(1,length(variable)-3),4);
You could then concatenate the two.
c = cats(a,b)
For the second, the COUNT function can be used to count occurrences of a string within a string:
http://support.sas.com/documentation/cdl/en/lefunctionsref/63354/HTML/default/viewer.htm#p02vuhb5ijuirbn1p7azkyianjd8.htm
Hope this helps :)

Answer 2

Make it a bit more general;
%let modeLength = 4;
%let maxOccur = 100; ** in the input **;
%let maxModes = 10; ** in the output **;
Where does a certain occurrence start?;
%macro occurStart(occurNo);
&modeLength.*&occurNo.-%eval(&modeLength.-1)
%mend;
Read the input;
data simplified ;
infile datalines truncover;
input v $%eval(&modeLength.*&maxOccur.).;
Declare output and work variables;
format what $&modeLength..
v1 $%eval(&modeLength.*&maxModes.).
v2 $&maxModes..;
array w {&maxModes.}; ** what **;
array c {&maxModes.}; ** count **;
Discover unique modes and count them;
countW = 0;
do vNo = 1 to length(v)/&modeLength.;
what = substr(v, %occurStart(vNo), &modeLength.);
do wNo = 1 to countW;
if what eq w(wNo) then do;
c(wNo) = c(wNo) + 1;
goto foundIt;
end;
end;
countW = countW + 1;
w(countW) = what;
c(countW) = 1;
foundIt:
end;
Report results in v1 and v2;
do wNo = 1 to countW;
substr(v1, %occurStart(wNo), &modeLength.) = w(wNo);
substr(v2, wNo, 1) = put(c(wNo),1.);
put _N_= v1= v2=;
end;
keep v1 v2;
The data I testes with;
datalines;
1996199619961996200120012001
197019801990
20011996199619961996200120012001
;
run;