# How to get all values existing in arrays/matrices?

40 views (last 30 days)
Arif Widianto on 24 Mar 2020
Edited: Andrei Bobrov on 24 Mar 2020
Hello,
Let say I have a 3-by-2 array with random integer values. For example,
myArray = [98 56; 58 52; 100 56];
What I want to do is, I want to get all value in the array and its frequency and save it to another array like this,
listValue = [98 1; 56 2; 58 1; 52 1; 100 1];
Is there any function or a way to do it?
Arif Widianto on 24 Mar 2020
Thank you for those who tried to answer my question.

Andrei Bobrov on 24 Mar 2020
Edited: Andrei Bobrov on 24 Mar 2020
[a,~,c] = unique(reshape(myArray',[],1),'stable');
out = [a, accumarray(c,1)];
or
out = varfun(@(x)x,array2table(myArray(:)),'GroupingVariables',1);
Arif Widianto on 24 Mar 2020
Edited: Arif Widianto on 24 Mar 2020
The first one works for my case. So, if I want it sorted, the only thing I need to do is changing 'stable' to 'sorted' right?
Andrei Bobrov on 24 Mar 2020
Edited: Andrei Bobrov on 24 Mar 2020
Yes or:
[a,~,c] = unique(myArray);
out = [a, accumarray(c,1)];

KSSV on 24 Mar 2020
Edited: KSSV on 24 Mar 2020
a = myArray(:) ;
[cnt_unique, unique_a] = hist(a,unique(a)) ;

Walter Roberson on 24 Mar 2020
See unique() and accumarray. Or unique and histc or histcounts (but be careful about the last value in histcounts). Or use a loop. Or use sparse(). Lots of ways.