Matlab: replace indices in a matrix

replace_indices.m

%% test data
% random seed
rng(1234567890);
% vector of original indices
A = (101:110)';
% random vector of new indices
% same length as A, can have duplicates
B = randi([1 10],length(A),1);
% random matrix with indices from A
MA = randi(A([1 end]),10,3);

%% in MA, replace A(i) by B(i)
% find positions of indices from A in MA
[check,mask] = ismember(MA,A);
% make sure all values have been found
assert(all(check(:)));
% replace
MB = B(mask);