topic Re: Create a binary variable from duplicate values in SAS Studio

Create a binary variable from duplicate values

Alireza_Boloori — Sat, 19 Aug 2017 00:43:58 GMT

Hello everyone,

Thanks in advance for your help!

I have a data like this:

X1 X2 X3 ...

1 ... ...

2 ... ...

3 ... ...

4 ... ...

and I want to create a new variable (called Y) with binary values, which makes the data as such:

X1 X2 X3 ... Y

1 ... ... 0

1 ... ... 1

2 ... ... 0

2 ... ... 1

3 ... ... 0

4 ... ... 0

4 ... ... 1

In other words, it puts 0 for a unique value of X1, 0 for the first non-unique value, and 1 for the remainder of non-unique values. I was wondering how it can be done in SAS. Any idea/help is really appreciated!

Re: Create a binary variable from duplicate values

Shmuel — Sat, 19 Aug 2017 00:51:33 GMT

Assuming data is sorted by X1 then do:

data want;
 set have;
  by X1;
       if first.x1  then y=0; else y=1;
run;

Re: Create a binary variable from duplicate values

Alireza_Boloori — Sat, 19 Aug 2017 00:55:34 GMT

@Shmuel Thank you for the answer!

Re: Create a binary variable from duplicate values

Reeza — Sat, 19 Aug 2017 00:57:46 GMT

Similar method, slightly different calculation, since that's exactly what FIRST does, flip the indicator.

data want;
 set have;
  by X1;

 y=1-first.x1;
run;

Re: Create a binary variable from duplicate values

Alireza_Boloori — Sat, 19 Aug 2017 00:59:20 GMT

@Reeza Thanks!