I have a cell array that contains multiple matrices of different size. I'd like to find & replace all elements of the matrices by a condition, e.g. replace all 1's with 0's. I found a temporary solution from find and replace values in cell array, but it seems way more complicated that it should be:
Example:
A = {[1 2;3 4] [1 2 3;4 5 6;7 8 9]}
replacement = 1:9;
replacement(replacement==1)=0;
A = cellfun(@(x) replacement(x) ,A,'UniformOutput',false)
A{:}
ans =
0 2
3 4
ans =
0 2 3
4 5 6
7 8 9
So it works but I feel like this should be doable without first specifying a list of replacement values and then "exchanging" all elements. (I have to do this a lot and with more complex conditions). Any suggestions?
One approach would be with elementwise-multiplication with the mask of such 1s -
cellfun(@(x) (x~=1).*x, A, 'uni',0)
Sample run -
>> celldisp(A) % Input cell array
A{1} =
3 2
1 4
A{2} =
7 1 3
4 5 1
7 8 9
>> C = cellfun(@(x) (x~=1).*x, A, 'uni',0);
>> celldisp(C)
C{1} =
3 2
0 4
C{2} =
7 0 3
4 5 0
7 8 9
Generic case : To make it generic that could replace any number by any other number, we need a slight modification, like so -
function out = replace_cell_array(A, oldnum, newnum)
out = cellfun(@(x) x+(x==oldnum).*(newnum-oldnum), A, 'uni',0);
Sample runs -
>> A = {[1 2;3 5] [1 2 3;5 5 3;7 8 9]}; % Input cell array
>> celldisp(A)
A{1} =
1 2
3 5
A{2} =
1 2 3
5 5 3
7 8 9
>> celldisp(replace_cell_array(A,1,0)) % replace 1s with 0s
ans{1} =
0 2
3 5
ans{2} =
0 2 3
5 5 3
7 8 9
>> celldisp(replace_cell_array(A,3,4)) % replace 3s with 4s
ans{1} =
1 2
4 5
ans{2} =
1 2 4
5 5 4
7 8 9