Mass concatenation using 'do loop' and arrays

[kai_cody]

I am trying to concatenate adult (A) and youth (Y) replicate weights together into a single column and there are 100 replicate weights of A and Y each. There are also four waves (W) of data, so I will end up creating a total of 400 concatenated variables. 

I'm a beginner when it comes to arrays and loops, but I had written a macro to try to accomplish this. I realized the macro worked, but it kept over-writing itself so that only the last 100th replicate weight concatenation remained created in the new dataset. Does anyone how to write an array/loop/macro to make this work efficiently? Much appreciated. 

%macro repweights (rep);

data All_Waves2; set All_Waves1;

W1_&rep=cats(R01_A_&rep, R01_Y_&rep);

W2_&rep=cats(R02_A_&rep, R02_Y_&rep);

W3_&rep=cats(R03_A_&rep, R03_Y_&rep);

W4_&rep=cats(R04_A_&rep, R04_Y_&rep);

%mend;

%repweights(1);

%repweights(2);

%repweights(3);

……

%repweights(100);

[PaigeMiller]

You want to concatenate 100 values into a single text string? I urge you to reconsider this, as there are most definitely simpler ways to handle such data. And with simpler ways to handle such data, you also get the benefit of simpler coding.

[kai_cody]

Hi Paige,

Thanks for your help.

I am trying to concatenate two columns into a single column but I need to do this 400 times. 

Wave 1 Adult 1 + Wave 1 Youth 1 = (concat Wave 1 Rep 1)

Wave 1 Adult 2 + Wave 1 Youth 2 = (concat Wave 1 Rep 2)

......

Wave 1 Adult 100 + Wave 1 Youth 100 = (concat Wave 1 Rep 100)

... and then repeat for Waves 2, 3, 4. 

[kai_cody · Accepted solution]

I was able to figure it out using arrays. Please note the original variable names were slightly abbreviated for simplicity in the original post and slightly differ from the variable names in this code below:

data All_Waves4; set All_Waves4a;

array adult1 (1:100) R01_A_PWGT1-R01_A_PWGT100;
array youth1 (1:100) R01_Y_PWGT1-R01_Y_PWGT100;
array Rep_W1_ (1:100);
do i=1 to 100;
Rep_W1_(i)=cats(adult1(i),youth1(i));
end; drop i;

array adult2 (1:100) R02_A_PWGT1-R02_A_PWGT100;
array youth2 (1:100) R02_Y_PWGT1-R02_Y_PWGT100;
array Rep_W2_ (1:100);
do i=1 to 100;
Rep_W2_(i)=cats(adult2(i),youth2(i));
end; drop i;

array adult3 (1:100) R03_A_AWGT1-R03_A_AWGT100;
array youth3 (1:100) R03_Y_AWGT1-R03_Y_AWGT100;
array Rep_W3_ (1:100);
do i=1 to 100;
Rep_W3_(i)=cats(adult3(i),youth3(i));
end; drop i;

array adult4 (1:100) R04_A_A01WGT1-R04_A_A01WGT100;
array youth4 (1:100) R04_Y_A01WGT1-R04_Y_A01WGT100;
array Rep_W4_ (1:100);
do i=1 to 100;
Rep_W4_(i)=cats(adult4(i),youth4(i));
end; drop i;

run;