Something similar to "paste" in R in SAS?

[Ruser]

Hi everybody!

I'm coming from R but am (unfortunaltely) forced to use SAS at the moment. So this might be some kind of beginner question .
I'm desperately looking for a similar function in SAS to the "paste" command in R.

To give you an idea:

I have 5 variables called V1a, V2a, V3a, V4a, and V5a in a data frame df, which are multiplied by some number n and asigned to 5 new variables V1b to V5b in the same data frame.
In R I would write a loop:

for i (1 to 5 ){

df[[ paste("V", i, "b", sep="" )]] <- df[[ paste( "V", i, "a", sep ="")]] * n

}

I have searched the SAS help and the net but found nothing similar to this in SAS. Does anyone know the tric, I can't imagine that it should not be possible to do this in SAS?

Thank you for reading.
Best!

[Dason]

The general concept that paste does is called "string concatenation" so searching for that might help. The following two pages might help:

This one gives some code but isn't how I would do it

Here you'd want to search for "string concatenation"

Hope this helps.

[Ruser]

Thank you very much, now I learned something new

Unfortulately this is not precisely what I'm looking for, my fault the question was ill posed. In both of your examples the modification is on data entries while I want to modify variable names. If I apply || || on a variable name I get an error:
"statement is not valid or is used out of proper order".
I have a huge amount of variable names that increase by one number in some or other way, fx. V99100, V99101, V99102, ..., or V99100, V99200, V99300,.... I have to do repeating operations on the variables and it would shorten the script (and the typing ) if I could just apply a do loop, like in the example.
So instead of writing

data test;
set test1;
V99101 = V99101 * n;
V99102 = V99102 * n;
....
run;

it would be much smarter to write

data test;
set test1;
do i=1 to m;
"V9910"+i = "V9910"+i * n;
end;
run;

Hm, can't be so hard after all.

[Mean Joe]

One way to do this is a macro. In SAS, macros are "code pasters".

*Define a macro: multiply a specific variable by a specific number*;
&#37;macro vn_mult;
%let i=1;
%do %while (&i<=9);
V9910&i = V9910&i * 100;
%let i = %eval(&i+1);
%end;
%mend vn_mult;

*Now you can call the macro (within a data step);
data test;
set test1;
%vn_mult;
run;


Note that this macro is limited: it only works for a variable with a specific name V9910i, and only multiplies by a specific number 100.

You can make it more general: when SAS parses the macro definition, when it gets to an &, it will replace the following string with the previously-referenced value for the string.

*More general macro, this one uses parameters in the definition;
%macro vn_mult_gen(varname, multiplier);
%let i=1;
%do %while (&i<=9);
&varname.&i = &varname.&i * &multiplier;
%let i = %eval(&i+1);
%end;
%mend vn_mult_gen;

data test;
set test1;
%vn_mult_gen(V9910, 100);
*This macro will multiply all variables V99101 thru V99109 by 100;
%vn_mult_gen(Va, 246);
*This macro will multiply all variables Va1 thru Va9 by 246;
run;

[Mean Joe]

Where R would say paste("V9910", i, sep="" ),
SAS says V9910.&i

The . tells SAS where to sep the base name from the suffix name. You can make multiple seps in SAS

eg V.&i.b would give you V1b thru V9b

[Ruser]

Thank you very much, you solved my problem, works fine now.

Here is a nice link concerning the subject:

http://www.stat.ubc.ca/~webmaste/how...ml#combinetext

[Ruser]

Hi again

now I'm coming with the next stupid question.

What if 'i' has breaks, fx. i = 1,3,4,5,8
Outside of macro world I would write:

do i = 1 3 4 5 8;
<code>
end;

But that doesn't work in the macro language.
I solved it so far by using an if-condition
but I like the other solution much better. Can anybody help (again)?

Thanks!