topic Re: What is the best way to implement this logic? in SAS Programming

What is the best way to implement this logic?

Fisher — Fri, 09 Nov 2012 19:15:27 GMT

Hi,

I have a data set like this:

data trend;

input tag $ @@;

datalines;

tr-c . . . tr-c tr-tr . .

;

run;

In this data set, I like to assign the missing tag values as the previous value except that after the tag value become the 'tr-tr', all the following missing values should be 'tr'. To make it clear, I like the final data set look like this:

data trend;

input tag $ @@;

datalines;

tr-c tr-c tr-c tr-c tr-c tr-tr tr tr

;

run;

This can be implemented using retain statement and lag function, but I think there should be some smarter way to implement it.

Thanks.

Re: What is the best way to implement this logic?

Haikuo — Fri, 09 Nov 2012 19:58:53 GMT

Try this:

data trend;

input tag $ @@;

length _tag $8;

retain _tag ;

_tag=coalescec(tag,_tag);

if missing(tag) then tag=ifc(_tag='tr-tr','tr',_tag);

drop _tag;

datalines;

tr-c . . . tr-c tr-tr . .

;

run;

Haikuo

Re: What is the best way to implement this logic?

Fisher — Fri, 09 Nov 2012 20:10:24 GMT

Excellent! I never tried this function, always learn something from SAS gurus here.

Thanks Hai.kuo.