Can I use ismember to compare a vector with a matrix
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Hi there,
Imagine I have an array and a matrix as below.
array_sample = [10;20;30]
matrix_sample = [15,35,10;22,33,44;55,25,30]
both array_sample and array_sample have the same number of rows.
Can anyone please tell me how to use ismember to compare each row in array_sample with each row in matrix_sample and output 1 if the array_sample element is present in the corresponding row of the matrix_sample ?
For the example given above the output should be
%% if I try something like this,
sample_out = ismemeber(array_sample, matrix_sample)
%% the output should be like this
sample_out = [1,0,1]' ; %% Because 10 and 30 are found respectively in 1st and 3rd row of matrix_sample.
Thank you.
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Answers (3)
Steven Lord
on 28 Aug 2020
Since you're using release R2019a (which supports implicit expansion) and your data is compatibly sized this is a job for the == operator and the any function.
array_sample = [10;20;30];
matrix_sample = [15,35,10;22,33,44;55,25,30];
sample_out = any(array_sample == matrix_sample, 2)
2 Comments
Steven Lord
on 28 Aug 2020
So you want to evaluate your objective function on a column vector where each element must come from the corresponding row of the matrix? So for your example matrix_sample your optimization routine would be allowed to evaluate the objective function with input [15; 33; 55] but not [15; 33; 54] (since 54 is not in the third row of matrix_sample)?
That's a very different question than the one you asked.
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