topic Re: How to Merge by Minimum Number of Observations in By Group? in SAS Procedures

How to Merge by Minimum Number of Observations in By Group?

jlajla — Wed, 16 Mar 2016 20:42:32 GMT

If I'm mot mistake, merge will, by default, make the total number of observations in the final data set set as the sum of the maximum number of observations in a BY-group from either data set.

How do I make the total number of observations in the final data set as the sum of the MINIMUM number of observations in the BY group from either data set?

I have this:

ID region

1 A

2 A

3 B

4 C

and

ID size

1 5

1 6

1 7

2 3

2 4

3 4

3 5

4 5

& I'd like:

ID region size

1 A 5

1 A 6

2 A 3

2 A 4

3 B 4

3 B 5

4 C 5

Thank you in advance.

Re: How to Merge by Minimum Number of Observations in By Group?

LinusH — Wed, 16 Mar 2016 20:31:35 GMT

How do you know that the first row in the "size" data set is the right one?

If you know, just use

if first.ID;

Assumng that there are no duplicates of ID in the "region" data set.

Re: How to Merge by Minimum Number of Observations in By Group?

jlajla — Wed, 16 Mar 2016 20:41:38 GMT

Thank you. I should elaborate. My first data set is actually similar to this:

1 A

2 A

3 B

4 C

And I'd like to match by the number of observations in this dataset. However, if I use first.id, then it only matches by the very first observation.

Re: How to Merge by Minimum Number of Observations in By Group?

LinusH — Wed, 16 Mar 2016 20:55:00 GMT

Perhaps you should share some real data, because this logic makes little sense.

Merging data without proper keys (unique by variables) leads to unpredictable results, and inconsistent data.

Re: How to Merge by Minimum Number of Observations in By Group?

Astounding — Wed, 16 Mar 2016 20:56:04 GMT

data minimum;

in1=0;

in2=0;

merge a (in=in1) b (in=in2);

by id;

if in1 and in2;

run;

Re: How to Merge by Minimum Number of Observations in By Group?

jlajla — Wed, 16 Mar 2016 21:42:14 GMT

Perfect. If modified to "if in1" this gives the exact results I needed. Thank you!