Find subscripts in a 3D matrix

11 Ansichten (letzte 30 Tage)
Fernando Montero
Fernando Montero am 28 Jan. 2021
Kommentiert: Fernando Montero am 28 Jan. 2021
I have a 3D matrix, called A, and I want to find the subscripts for all places where elements of vector B appear. The elements of B apper more than one time in the matrix A.
I tried it using function subs to obtain directly the susbsripts, but I obtained a result where many page numbers are wrong (it shows a higher number (5) than the existing pages (3)). Bellow the code:
A(:,:,1)=[1 2 ; 3 3 ; 5 7 ; 4 2];
A(:,:,2)=[9 1 ; 4 4 ; 9 2 ; 4 6];
A(:,:,3)=[2 4 ; 7 4 ; 3 1 ; 6 4];
B = [9 4 1];
[row,col,page] = ind2sub(size(A),find(A(:)==B))
Also I tried using function find to obtain the linear indexes to later convert them to subscripts; however, I only obtain the first place were the element is placed on the matrix:
n = arrayfun(@(x) find(A==x,1),B);
[row, col, page] = ind2sub(size(A), n);

Akzeptierte Antwort

Walter Roberson
Walter Roberson am 28 Jan. 2021
A(:,:,1)=[1 2 ; 3 3 ; 5 7 ; 4 2];
A(:,:,2)=[9 1 ; 4 4 ; 9 2 ; 4 6];
A(:,:,3)=[2 4 ; 7 4 ; 3 1 ; 6 4];
B = [9 4 1];
[row,col,page] = ind2sub(size(A),find(ismember(A,B)))
row = 12×1
1 4 1 2 3 4 1 2 1 2
col = 12×1
1 1 1 1 1 1 2 2 2 2
page = 12×1
1 1 2 2 2 2 2 2 3 3
  4 Kommentare
Walter Roberson
Walter Roberson am 28 Jan. 2021
find(ismember(A,B)) would be linear
sub2ind(size(A), row,col,page)
if you need to reconstruct linear
Fernando Montero
Fernando Montero am 28 Jan. 2021
Thanks again!

Melden Sie sich an, um zu kommentieren.

Weitere Antworten (0)

Kategorien

Mehr zu Spline Postprocessing finden Sie in Help Center und File Exchange

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by