MATLAB: Creating a conditional variable or function such that

Question

Hi, I'm struggling for hours to do this…

Suppose I have this data:

schoolid classid classsize enrollment newcolumn

1001 1 10 22 11

1001 2 12 22 11

1005 1 14 29 14.5

1005 2 15 29 14.5

1018 1 8 22 22/3

1018 2 4 22 22/3

1018 3 10 22 22/3

.

.

.

I would like to generate a function that gives "newColumn" above.

Plaese help me out. Thanks.

Answer 1

Try this

schoolID = [1001 1001 1005 1005 1018 1018 1018];
enrollment = [22 22 29 29 22 22 22];
 
grps = findgroups(schoolID);
avg = splitapply(@(x) x(1)/numel(x), enrollment.', grps.');
newcolumn = avg(grps);