How to count the total number of occurrences of each digit in cell arrays?
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Md Shahidullah Kawsar
on 7 Nov 2018
Edited: pedro antonio solares hernandez
on 29 Apr 2020
Suppose I have a cell array
C = {[1; 4; 7]; [2; 5; 8; 9]; [3; 4]};
c{:}
ans =
1
4
7
ans =
2
5
8
9
ans=
3
4
% where any digit won't repeat in the individual cell.
% There are 4 stages in this cell array.
% first stage elements are 1, 2, 3
% second stage elements are 4, 5, 4
% third stage elements are 7,8
% fourth stage elements are 9
I need to count the total number of occurrences of each digit in stage 2. Expected output:
Digit | Number of occurrences
4 2
5 1
1 Comment
Guillaume
on 7 Nov 2018
Your concept of stage is badly thought. You would be much better off storing stages as element of the cell array rather than scattering them across the elements. So:
c = {[1 2 3], [4 5 4], [7 8], 9]}
As it is you will have to programmatically convert your existing cell array into the above to do your histogram any way.
Accepted Answer
Stephen23
on 7 Nov 2018
>> C = {[1; 4; 7]; [2; 5; 8; 9]; [3; 4]};
>> V = cellfun(@(v)v(2),C);
>> U = unique(V);
>> N = histc(V,U);
>> [U,N]
ans =
4 2
5 1
3 Comments
Stephen23
on 7 Nov 2018
Edited: Stephen23
on 7 Nov 2018
"What if I also want to include stage 3 and stage 4?"
% Your data:
C = {[1;4;7]; [2;5;8;9]; [3;4]}
% Convert cell array:
X = cellfun(@(v)1:numel(v),C,'uni',0);
X = accumarray([X{:}].',vertcat(C{:}),[],@(v){v})
for k = 1:numel(X)
U = unique(X{k});
N = histc(X{k},U);
[U,N]
end
Giving:
ans =
1 1
2 1
3 1
ans =
4 2
5 1
ans =
7 1
8 1
ans =
9 1
Method two: alternatively you could use nested loops and a cellfun call to check the length of the cell contents. The use a loop:
C = {[1;4;7]; [2;5;8;9]; [3;4]}
L = cellfun('length',C)
for k = 1:max(L)
V = cellfun(@(v)v(k),C(L>=k));
U = unique(V);
N = histc(V,U);
[U,N]
end
Giving:
ans =
1 1
2 1
3 1
ans =
4 2
5 1
ans =
7 1
8 1
ans =
9 1
pedro antonio solares hernandez
on 29 Apr 2020
Edited: pedro antonio solares hernandez
on 29 Apr 2020
Hello!; it's posible to compute with this example the elements from rows? In this example, the results coming from the columns.
For example, if i have the array C = {[1,1,7,2]; [2,5,8,6]; [3,4,2,2,4,3]}, ill like to have the next result:
row 1:
1-> 2
2-> 1
7->1
row 2:
2-> 1
5-> 1
6-> 1
8-> 1
row 3:
2-> 2
3-> 2
4-> 2
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