topic Re: what is the difference betwwe multiple "if" and one if with multiple condition? in SAS Programming

what is the difference betwwe multiple "if" and one if with multiple condition?

Phil_NZ — Mon, 14 Jun 2021 06:01:09 GMT

Hi all, I have the code below

DATA want;
 SET have;
 If cvt_yr=-4 then dkt_4=1;
 else if cvt_yr=-3 then dkt_3=1;
 else if cvt_yr=-2 then dkt_2=1;
 else if cvt_yr=-1 then dkt_1=1;
 else if cvt_yr=0 then dkt=1;
 else if cvt_yr=1 then dkt1=1;
 else if cvt_yr=2 then dkt2=1;
 else if cvt_yr=3 then dkt3=1;
 else if cvt_yr>=4 then dkt4=1;
run;

I am wondering what is the difference between this code with

DATA want;
 SET have;
 If cvt_yr=-4 then dkt_4=1;
 if cvt_yr=-3 then dkt_3=1;
 if cvt_yr=-2 then dkt_2=1;
if cvt_yr=-1 then dkt_1=1;
  if cvt_yr=0 then dkt=1;
  if cvt_yr=1 then dkt1=1;
 if cvt_yr=2 then dkt2=1;
  if cvt_yr=3 then dkt3=1;
 if cvt_yr>=4 then dkt4=1;
run;

Re: what is the difference betwwe multiple "if" and one if with multiple condition?

ChrisNZ — Mon, 14 Jun 2021 06:26:37 GMT

The result will be the same in this precise case, but the first code is more efficient as not all tests are executed.

Also please align/format your code properly 🙂 This is much helped by never using tabs and using spaces instead. This way any cut-and-paste is sure to retain the original format.

Re: what is the difference betwwe multiple "if" and one if with multiple condition?

Phil_NZ — Mon, 14 Jun 2021 06:38:40 GMT

Thanks @ChrisNZ

Next time I will Ctrl+I before paste.

Have a good week!

Re: what is the difference betwwe multiple "if" and one if with multiple condition?

japelin — Mon, 14 Jun 2021 06:42:36 GMT

The same is true for this condition.

However, repeating if may cause unintended conditional branches in data and conditions. For exclusive cases, it is better to use if-else or select-when.