Using a column vector of indices to replace values in a matrix
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Teddy Fisher
am 13 Dez. 2019
Kommentiert: sruizpp
am 18 Nov. 2020
Hello,
I have a column vector, C, (55x1 double) which are the indices of my values of interest in Matrix, M which is 370x29 double.
I want to replace all the values in M that are not these values of interest with 0.
I am trying to use C to index into M and replace ~C with 0.
However when I try
M(~C)=0
all it does is change all the values in M to just different values and I'm not sure why.
When I try to create a new Matrix
N=M(~C==0) it returns a columnn vector with just the first 55 values in the first column of M.
Does anyone know how I can replace all the elements in M that are not listed in C with 0? I want my output to be another 370x29 double matrix.
Thanks!
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Akzeptierte Antwort
Fangjun Jiang
am 13 Dez. 2019
Bearbeitet: Fangjun Jiang
am 13 Dez. 2019
C=[1,2,3]';
M=magic(5);
index=setdiff(1:numel(M),C);
M(index)=0
2 Kommentare
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Guillaume
am 13 Dez. 2019
Bearbeitet: Guillaume
am 13 Dez. 2019
Well, now you have explained how you got C, a much simpler method than the accepted one is not to create C and use:
M(~R) = 0; %that's all that is needed!
As usual in matlab, find is completely unnecessary and what you were trying to do initially would have worked had you kept your original logical vector.
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