hello
try this
%% dummy data
B = ([1 1 1 1 2 2 2 4 4 4 4 1 1 1 1 2]/8)'; % 2nd column data
A = 100*rand(size(B))'; % first column data
%% main code
Bu = unique(B);
for ci = 1:numel(Bu)
ind = (B == Bu(ci));
A_extract_mean(ci,1) = mean(A(ind));
end
C = [A_extract_mean Bu] % First colums contains average values according to the 2nd column values of E1
