topic Re: Append datasets in SAS Programming

Append datasets

leahcho — Fri, 08 Dec 2017 12:27:05 GMT

Hi,

I have datasets that have multiple lines for person IDs and not sure if I can append these datasets.

So my data contain;

Dataset1

ID A B C

1 1 2 .

1 . . 3

1 1 . .

2 1 3 1

2 . 2 1

2 . 2 .

Dataset 2

ID A B C

3 1 2 .

3 . . 3

3 1 . .

4 1 3 1

4 . 2 1

4 . 2 .

Is it possible to append dataset 1 and 2 and retain all the data in those datasets?

Thanks.

Re: Append datasets

PeterClemmensen — Fri, 08 Dec 2017 12:29:56 GMT

data Dataset1;
input ID$ A B C;
datalines;
1 1 2 .
1 . . 3
1 1 . .
2 1 3 1
2 . 2 1
2 . 2 .
;

data Dataset2; 
input ID$ A B C;
datalines;
3 1 2 .
3 . . 3
3 1 . .
4 1 3 1
4 . 2 1
4 . 2 .
;

data want;
	set Dataset1 Dataset2;
run;

Re: Append datasets

RW9 — Fri, 08 Dec 2017 13:47:45 GMT

Just to add, you may want to use proc append, it should be quicker than a datastep as it doesn't read the data:

http://support.sas.com/documentation/cdl/en/proc/61895/HTML/default/viewer.htm#a000070936.htm

Re: Append datasets

Enio — Fri, 08 Dec 2017 14:21:47 GMT

Hi,

Combining both into a third dataset using a set statement is very common, but it is a great habit to get into using proc append as (mentioned already) this can have significant performance benefits when working with large datasets. (Many thanks to @PeterClemmensen as I shamelessly copied your code to start with!)

This example will simply append dataset2 onto dataset1:

data Dataset1;
input ID$ A B C;
datalines;
1 1 2 .
1 . . 3
1 1 . .
2 1 3 1
2 . 2 1
2 . 2 .
;

data Dataset2; 
input ID$ A B C;
datalines;
3 1 2 .
3 . . 3
3 1 . .
4 1 3 1
4 . 2 1
4 . 2 .
;

proc append base=dataset1 data=dataset2; run;

Re: Append datasets

PeterClemmensen — Fri, 08 Dec 2017 14:22:49 GMT

Shame on you @Enio! 😉

And I agree completely with @RW9 and @Enio, PROC APPEND is the way to go if you take performance into account.

Re: Append datasets

leahcho — Fri, 08 Dec 2017 21:31:30 GMT

Thanks guys for your help!