topic Re: IF Statements Problem: How to keep more? in SAS Programming

IF Statements Problem: How to keep more?

audreyliu201 — Mon, 06 Nov 2017 03:35:23 GMT

data west;
set x;
IF no="04";
IF no="21";
IF no="23";
run;

There is a variable NO. I would like to keep no=04, no=21 and no=23 at the same time.

However, This code doesn't work.

Besides, I run it one by one and then set together. Is there any other way else to do it?

Re: IF Statements Problem: How to keep more?

ChrisNZ — Mon, 06 Nov 2017 04:05:33 GMT

if NO = '04';

is the same as

if NO ne '04' then delete;

It means: only keep if NO='04' .

You want

if NO in ('04','21','23');

Re: IF Statements Problem: How to keep more?

audreyliu201 — Mon, 06 Nov 2017 04:07:50 GMT

Thank you. This is very clean and simple

Re: IF Statements Problem: How to keep more?

RW9 — Mon, 06 Nov 2017 09:25:22 GMT

You would be better off storing those numeric values as numeric variables rather than text, unless there is a really good reason not to. For instance, calculations, where's, joins etc. all will work better with numerics, and if you say you need the 0 where only one digit is present, then use the z2. format. Best of both worlds then.

if no in (4,21,23);

Re: IF Statements Problem: How to keep more?

ChrisNZ — Mon, 06 Nov 2017 10:27:20 GMT

@RW9 Good point. Another school of thought is that numeric variables should only be for values that can be used for calculations, and other values (like IDs) should be strings. Strings do need to use exact values ( '9' is not the same as ' 9' or '09' ) but this is not necessarily detrimental. I reckon the difference is just something to be aware of, not a reason to always use one or the other.

As for speed, strings can be be faster when merging.

data T1 T2;  do I=1 to 1e8-1; output; end;
data _null_; 
  merge T1 T2; by I; 
run;
*NOTE: DATA statement used (Total process time):
       real time           27.15 seconds
       user cpu time       25.14 seconds
       system cpu time     2.01 seconds;


data T1 T2;  do I=1 to 1e8-1; A=put(I,z8.);output; end; drop I;
data _null_; 
  merge T1 T2; by A; 
run;
*NOTE: DATA statement used (Total process time):
       real time           25.58 seconds
       user cpu time       23.13 seconds
       system cpu time     2.44 seconds;