Finding row indexes in array

I have an array

 a=[0 0 1 0 ; 1 2 3 0; 1 0 3 4; 0 2 0 0 ]

& cell array like

 b{1,1}=[4;3]
 b{2,1}=[3;1;4]

I want to find elements of cell array in a. For example: for b{2,1} 1st, 3rd and 4th row of a should be displayed and 2nd should be zero.

Thanks in advance

Answer 1

[Andrei Bobrov]

a=[0 0 1 0 ; 1 2 3 0; 1 0 3 4; 0 2 0 0 ];
b{1,1}=[4;3];
b{2,1}=[3;1;4];

v = 1:size(a,1);
t = cell2mat(cellfun(@(x)ismember(v,x),b,'un',0))';
out = a.*permute(t,[1,3,2]);

[lucksBi]

Thank you so much. This is exactly what i want. Can I get final result in cell array other than 3D array?

[Andrei Bobrov]

Yes.

a=[0 0 1 0 ; 1 2 3 0; 1 0 3 4; 0 2 0 0 ];
b{1,1}=[4;3];
b{2,1}=[3;1;4];

out = cellfun(@(x)a.*ismember((1:size(a,1))',x),b,'un',0);

[lucksBi]

Thanks alot

[lucksBi]

It is working fine on small matrix e.g i tried on 6x6 matrix size it is giving accurate results. But when i tried it on matrix of size 943x943, it gives following error. ??? Error using ==> times Matrix dimensions must agree.

Error in ==> @(x)a.*ismember((1:size(a,1))',x) Error in ==> file2 at 22 out=cellfun(@(x)a.*ismember((1:size(a,1))',x),b,'un',0);

can you please help on this.

[Andrei Bobrov]

Please attach your data that gives an error.

[lucksBi]

here are .mat files of a & b matrices

[lucksBi]

hey can you please help on this matter? i am unable to fix this issue with with given mat files.

Answer 2

[Thorsten]

idx = cellfun(@(x) any(ismember(a, x)), b, 'UniformOutput', false);
rows = cellfun(@(x) a(:, x), idx, 'UniformOutput', false);

Or in one line:

rows = cellfun(@(x) a(:, any(ismember(a, x))), b, 'UniformOutput', false);

[lucksBi]

Thanks Alot. But it gives 4x2 array for b{1,1}, (changes no of columns in each cell) i want a 4x4 array with elements of rows that are member of b and other rows as zero.

[Thorsten]

Like this?

idx = cellfun(@(x) any(ismember(a, x)), b, 'UniformOutput', false);

a0 = zeros(size(a));
for i = 1:numel(idx)
  rows{i} = a0;
  rows{i}(:,idx{i}) = a(:,idx{i});
end

[lucksBi]

result should be like: result{1,1}= [0,0,0,0;0,0,0,0;1,0,3,4;0,2,0,0] result{1,2}= [0,0,1,0;0,0,0,0;1,0,3,4;0,2,0,0]