How to count unique elements of a cell in Matlab?
I want to count the unique elements of a cell array in Matlab. How can i do this? Thank.
c = {'a', 'b', 'c', 'a'};
% count unique elements, return the following struct
unique_count.a = 2
unique_count.b = 1
unique_count.c = 1
+2
Martin08
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2 answers
To count unique elements, you can combine UNIQUE with ACCUMARRAY
c = {'a', 'b', 'c', 'a'};
[uniqueC,~,idx] = unique(c); %# uniqueC are unique entries in c
%# replace the tilde with 'dummy' if pre-R2008a
counts = accumarray(idx(:),1,[],@sum);
To create a structure, use NUM2CELL and STRUCT :
countCell = num2cell(counts);
tmp = [uniqueC;countCell']; %'
unique_count = struct(tmp{:}) %# this evaluates to struct('a',2,'b',1,'c')
unique_count =
a: 2
b: 1
c: 1
+7
Jonas
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Look count_unique in file sharing. He uses accumarray
or sort
whichever is most appropriate. It will also check for nans / infs.
+1
Rich c
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