SAS How to concatenate strings several times in the same variable during a data step

Question

A very basic question.

How come I cannot change a variable in a datastep like this?

data want;
   aaaaa='[';
   aaaaa=cats(aaaaa,'hello');
   aaaaa=cats(aaaaa,']');
   put aaaaa;
run;

aaaaa will be equal to '[' , I expect '[hello]'

I need to define aaaaa in multiple steps because I need to construct aaaaa with do loops (with unpredictable length), I can't define aaaaa in just one step.

Thanks!

Do you really want to do put for aaaaa variable? the value for aaaaa in table want equals [hello]. — andrey_sz, Jul 14 '16 at 09:00
Also look into `call cats` as it saves you having to specifiy `aaaaa = cats(aaaaa, ......)` — Longfish, Jul 14 '16 at 11:16
@Keith `aaaaa=cats(aaaaa,'bbbbb');` would be equivalent to `call cats(aaaaa,aaaaa,'bbbbb');`? I don't see what's the advantage of that. It's even longer. — stallingOne, Jul 14 '16 at 12:11

score 3 · Accepted Answer · answered Jul 14 '16 at 09:06

3

When first calling aaaaa SAS will assign a length to the variable. In this case length aaaaa $1 as you only assign one character. SAS data types are not dynamic. Start your datastep by assigning your variable a fixed length that covers the maximal expected length e.g.

data want;
    length aaaaa $300;
    aaaaa='[';
    aaaaa=cats(aaaaa,'hello');
    aaaaa=cats(aaaaa,']');
    put aaaaa;
run;

answered Jul 14 '16 at 09:06

Jetzler

787
3
11

I was pretty sure it was something stupid I missed :-). Thanks! – stallingOne Jul 14 '16 at 09:09

score 1 · Answer 2 · answered Jul 14 '16 at 09:06

1

You can add attrib or format statement to data-step:

data want;
   attrib 
      aaaaa format=$200.;
   aaaaa='[';
   aaaaa=cats(aaaaa,'hello');
   aaaaa=cats(aaaaa,']');
   put aaaaa;
run;

answered Jul 14 '16 at 09:06

andrey_sz

751
1
13
29

score 0 · Answer 3 · answered Jul 14 '16 at 12:44

0

As per my comments, here's an alternative way using call cats.

data want;
length aaaaa $300;
call cats(aaaaa,'[');
call cats(aaaaa,'Hello');
call cats(aaaaa,']');
run;

answered Jul 14 '16 at 12:44

Longfish

7,582
13
19

SAS How to concatenate strings several times in the same variable during a data step

3 Answers3