How to change all matrix values according to a list

user_18421390 0
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I have a 500x500 sparse matrix with values ranging from 0 to a.

I want to change its elements according to a list working as a dictionary. Elements that equal 1 become the value of list(1), that equal 2 become the value of list(2), etc until values that equal a become list(a)

Is there a simple way to do this?

sparse-matrix matlab
2 Answers

This can be done by at least three methods:

  • method1

     [r, c, v] = find(m);
 m = sparse(r, c, list(v), size(m,1), size(m,2));

  • method2

    m(find(m)) = list(nonzeros(m));

  • method3

    m = spfun(@(x)list(x), m);
user_65797440

Assuming your sparse matrix contains only integers between 0 and a, here is one way using logical indexing:

S = your sparse matrix
L = logical(S);  % mask of elements to replace
S(L) = list(S(L));  % replace mask elements with corresponding list elements
user_46566010
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