MATLAB: List the result of the index values in ranges

arrayfindindexingrange

Hello,
I have an array that is populated with the values 1,2 or 3.
   a = [1 1 2 2 3 3 2 2 1 1];
and I want to list the ranges of each value. The find function retrieves the index to each number which is great.
   [col1] = find(a==1)
   [col2] = find(a==2)
   [col3] = find(a==3)
but is there a function or some logic i can use to list col1, col2, and col3 as ranges? as in col1 = 1-2 and 9-10 and col2 = 3-4 and 7-8 etc etc.
I appreciate any ideas or help.
Thank you in advance!

Best Answer

A = [1 1 2 2 3 3 2 2 1 1];
X = arrayfun(@(k) find(A==k),1:3,'un',0) ;
Y = cellfun(@(v) [v([true diff(v) > 1]) ; v([diff(v) > 1 true])]', X,'un',0) ;
% Y{k} contains the start indices (1st column) and end indices (2nd column) for a sequence of the value k in A
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