How can i index lower dimensions of a matrix by another matrix of lower dimension?

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Baris Kiliclar 2020-3-26

编辑： Stephen23 2020-3-27

Hello guys,

I want to index lower dimensions by a logical matrix for example:

A is m by n by 3 array. (uint8 RGB image )

B= m by n logic array. Following assignment doesn't work.

A(B,:)=0 ;

How can i do that in the simplest way ? (wtihout assigning 3 channels separetely)

Thanks,

Barış Kılıçlar

Stephen23 2020-3-26

编辑：Stephen23 2020-3-27

"...wtihout assigning 3 channels separetely"

Assigning the three columns separately is probably the simplest and most efficient way.

Baris Kiliclar 2020-3-27

From "...wtihout assigning 3 channels separetely" , i just want to avoid the following sequence:

Ar=A(:,:,1);
Ag=A(:,:,2);
Ab=A(:,:,3);
Ar(B)=0;
Ag(B)=0;
Ab(B)=0;
C=cat(3,Ar,Ag,Ab);

which is very long, inefficient and boring.

But, your suggestion at somewhere in the post you gave the link above: (translated to the terms in this post)

A(B(:,:,[1,1,1]))=0;

is quite satisfactory and elegant for my actual needs.

Thank you very much.

Barış Kılıçlar

MATLAB Language Fundamentals Matrices and Arrays Matrix Indexing

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