## concatenate multiple columns

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Occasional Contributor
Posts: 15

# concatenate multiple columns

[ Edited ]

Hello,

I have a data set that I'd like to have a few column concatenated into one colum. The data set and variables are like this:

(10 variables)

department item cat1 cat2 cat3 cat4 cat5 nt1 nt2 nt3
aaa        v    1a   2a   3a   4a   5a   1a  2a
bbb        w    1b   2b   3b             1b  2b  3b
ccc        x    1c   2c   3c   4c        1c  2c  3c
ddd        y    1d   2d   3d   4d   5d   1d  2d  3d

The end table should look like this (3 variables):

department item newvar
aaa        v    1a, 2a, 3a, 4a, 5a, 1a, 2a
bbb        w    1b, 2b, 3b, 1b, 2b, 3b
ccc        x    1c, 2c, 3c, 4c, 1c, 2c, 3c
ddd        y    1d, 2d, 3d, 4d, 5d, 1d, 2d, 3d

These cat and nt variables are obtained by joining two tables (catTable and ntTable) so we have the option of working with one table at a time and concatenating twice, but the number of cat and nt variables can vary at any time so concatenating needs to be dynamic.

I thought about using this SAS option to create a macro but didn't know how to make the macro variable work. Thanks in advance for your help.

``````dsid1 = open("catTable");
dsid2 = open("ntTable");
&num_cat = attrn(dsid1,"NVARS")-2;
&num_nt = attrn(dsid2,"NVARS")-2;``````

Accepted Solutions
Solution
‎02-15-2016 03:50 PM
Posts: 1,256

## Re: concatenate multiple columns

Hello @mhouse,

If the "cat and nt variables" have these numbered names, you could try the second of these two steps:

``````data have;
input (department item cat1 cat2 cat3 cat4 cat5 nt1 nt2 nt3) (:\$3.);
cards;
aaa        v    1a   2a   3a   4a   5a   1a  2a  .
bbb        w    1b   2b   3b    .    .   1b  2b  3b
ccc        x    1c   2c   3c   4c    .   1c  2c  3c
ddd        y    1d   2d   3d   4d   5d   1d  2d  3d
;

data want;
set have;
newvar=catx(', ', of cat:, of nt:);
drop cat: nt:;
run;``````

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Super User
Posts: 23,771

## Re: concatenate multiple columns

Declare an array that contains the max amount of variables then use CATX. You appear to be filling in missing values? You'll have to account for that logic.

``````array vars(*) cat1-cat&num_cat nt1-nt&num_nt;

new_var = catx(",", of vars(*));``````

Solution
‎02-15-2016 03:50 PM
Posts: 1,256

## Re: concatenate multiple columns

Hello @mhouse,

If the "cat and nt variables" have these numbered names, you could try the second of these two steps:

``````data have;
input (department item cat1 cat2 cat3 cat4 cat5 nt1 nt2 nt3) (:\$3.);
cards;
aaa        v    1a   2a   3a   4a   5a   1a  2a  .
bbb        w    1b   2b   3b    .    .   1b  2b  3b
ccc        x    1c   2c   3c   4c    .   1c  2c  3c
ddd        y    1d   2d   3d   4d   5d   1d  2d  3d
;

data want;
set have;
newvar=catx(', ', of cat:, of nt:);
drop cat: nt:;
run;``````
Occasional Contributor
Posts: 15

## Re: concatenate multiple columns

Thank you @Reeza and @FreelanceReinhard! I didn't know how to make the macro variables work without writing a full macro but the second solution worked for my purpose.

Thanks again,

mhouse

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