Upcase(group) in ('A','B')

[dooheekim01]

The question is:

• create a temporary data set, cleandata36.
• In this data set, convert all group values to upper case.
• Then keep only observations with group equal to 'A' or 'B'.

The answer is:

data work.cleandata36;
set cert.input36;
if upcase(group) in ('A','B');
run;

I don't understand since there is no 'then do' or anything after if upcase(group)in ('A', 'B'). Could you explain why? Thanks. 

[Rick_SAS]

This is called the "subsetting IF statement". It does not use a THEN clause. Think of it like a filter: Only observations that satisfy the IF condition are output to the data set.

[PaigeMiller]

---

@dooheekim01 wrote:

The question is:

• create a temporary data set, cleandata36.
• In this data set, convert all group values to upper case.
• Then keep only observations with group equal to 'A' or 'B'.

The answer is:

data work.cleandata36;
set cert.input36;
if upcase(group) in ('A','B');
run;

I don't understand since there is no 'then do' or anything after if upcase(group)in ('A', 'B'). Could you explain why? Thanks. 

---

The code would work, except that it does not do this part of the question: "convert all group values to upper case", so the output data set could contain lowercase 'a' or lowercase 'b'. You need one more statement to make all the values uppercase.

[ballardw · Accepted solution]

The IF without a then is called a subsetting IF. It means "only keep records if the condition is true".

BTW that is not actually a correct answer. There is nothing that makes the values upper case to keep.

If the values are lower case they will still be so in the output.

data junk;
  input group $;
datalines;
a
b
c
d
e
g
junk
;

data want;
   set junk;
   if upcase(group) in ('A','B');
run;

Note that group = "a" and "b" are in the output.

there should be a statement like:

   group = upcase(group);

if the values in the output set are supposed to be upper case.

[dooheekim01]

Thank you so much!

[wwwz]

I have another question for the upcase function and the in operator. 

I used:

Upcase(group) in (upcase('a'), upcase('b'));

But it does NOT work, showing error message.

Please help.

Thanks

[Rick_SAS]

As stated in the documentation for the IN operator, the list of values on the right side must be CONSTANT values, not expressions.

[wwwz]

Thanks, I see.

[anming]

the similar omissions can be found in the following cases;

proc sort data = scoredata_p;
by stu_id;
run;

proc sort data = scoredata;
by stu_id;
run;

data MMA;
merge scoredata_p(in = A) scoredata (in = B);
by stu_id;
if A and B;
run;

in selected variable merge (stu_id), you can omit A=1 and B=1 in 'if' statement.

[TS4]

why it gives different answer if i use where statement instead of if statement.