MATLAB: Ismember in a different way

binarisingbinaryindexingismember

Hello all, I have a vector X with numbers. These X vector numbers are numbers (indeces) for columns of another vector Y that are significant. Now I want to binarize my vector Y and set the values in Y that correspond with the indeces provided by vector X to 1s, and the rest of the vector Y to 0s.
example:
X = [1 2 5 9]; Y = [10 12 3 43 75 60 67 8 90]
result: Y = [1 1 0 0 1 0 0 0 1]
I tried to do it with ismember, but I do not think it will work for indexing – could you help? Thanks.

Best Answer

The values of Y do not matter in any way, do they?
X = [1 2 5 9];
Y = [10 12 3 43 75 60 67 8 90];
Y(:) = 0;  % Set all to 0
Y(X) = 1;  % Set elements at position X to 1
Or if you really want ismember, but this is less efficient:
Y = ismember(1:numel(Y), X);
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