remove all strings from nested cell array

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Hi,
I'm trying to remove all string/chars from a 4x10 cell array where each cell in the array contains a 40x1 column vector (so as you can see, it's nested). Most commands I usually use such as cell2mat don't work on this because the cell array is nested.
Or, if preferred, is there a way to read in all the elements of a certain column in one of the cells in a cell array apart from the elements containing strings? e.g:
col=rand(4,10) %matrix containing column indices
for i=1:4
for j=1:10
new_cell_arrray{i,j}=g{i,1}(:,col(i,j)); %g is another (existing) 4x1 cell array and new_cell_array is 4x10.
end
end
Thank you
  1 Comment
Walter Roberson
Walter Roberson on 22 Jun 2022
If you "remove" an entry from a 2D array, the result cannot be a 2D array any more.

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Accepted Answer

Walter Roberson
Walter Roberson on 22 Jun 2022
C = num2cell(randi(9,4,10));
C(randperm(numel(C), 4)) = {"string"};
C(randperm(numel(C), 4)) = {'chars'};
C
C = 4×10 cell array
{[5]} {[ 8]} {[5]} {[6]} {[1]} {[ 8]} {'chars'} {'chars' } {["string"]} {'chars'} {[3]} {["string"]} {[4]} {[1]} {[2]} {["string"]} {[ 1]} {[ 9]} {[ 5]} {[ 8]} {[8]} {[ 5]} {[4]} {[8]} {[9]} {[ 2]} {[ 1]} {[ 5]} {[ 6]} {[ 7]} {[3]} {[ 3]} {[5]} {[1]} {[5]} {[ 2]} {'chars'} {["string"]} {[ 9]} {[ 8]}
for K = 1 : size(C,2)
mask = ~cellfun(@(c)ischar(c)||isstring(c), C(:,K));
subset{K} = C(mask, K);
end
subset
subset = 1×10 cell array
{4×1 cell} {3×1 cell} {4×1 cell} {4×1 cell} {4×1 cell} {3×1 cell} {2×1 cell} {2×1 cell} {3×1 cell} {3×1 cell}
subset{1}, subset{2}
ans = 4×1 cell array
{[5]} {[3]} {[8]} {[3]}
ans = 3×1 cell array
{[8]} {[5]} {[3]}
  5 Comments
Walter Roberson
Walter Roberson on 24 Jun 2022
"In each cell, I have 4 strings and 36 numbers."
Okay, I will generate 4 strings and 36 numbers per cell.
for J = 1 : 4
for K = 1 : 10
thiscell = num2cell(randi(9, 40, 1));
rp = randperm(40,4);
thiscell(rp) = {"string"};
C{J,K} = thiscell;
end
end
whos C
Name Size Bytes Class Attributes C 4x10 206080 cell
C{1}
ans = 40×1 cell array
{[ 4]} {[ 1]} {[ 4]} {[ 4]} {[ 1]} {[ 3]} {[ 1]} {[ 6]} {[ 4]} {["string"]} {[ 4]} {[ 7]} {["string"]} {[ 1]} {[ 3]} {[ 5]}
subset = cell(size(C));
for J = 1 : numel(C)
mask = ~cellfun(@(c)ischar(c)||isstring(c), C{J});
subset{J} = C{J}(mask);
end
whos subset
Name Size Bytes Class Attributes subset 4x10 165440 cell
subset{1}
ans = 36×1 cell array
{[4]} {[1]} {[4]} {[4]} {[1]} {[3]} {[1]} {[6]} {[4]} {[4]} {[7]} {[1]} {[3]} {[5]} {[5]} {[5]}
and see that after the filtering, there are 36 entries left. All of the string() objects and character vectors have been removed.

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