counts of unique value in array in matlab

To count the number of unique values in an array in MATLAB, you can use the built-in unique function followed by the numel function to determine the count. Here's an example code snippet:

main.m
a = [1 2 3 4 5 4 3 2 1];
uniqueValues = unique(a);
numberOfUniqueValues = numel(uniqueValues);
disp(numberOfUniqueValues) % Output: 5
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In this example, we have an array a with 9 elements, including some repeated values. We use the unique function to obtain an array of the unique values in a. We then use the numel function to determine the number of elements in the uniqueValues array, which gives us the count of unique values in a.

Note that the unique function also returns the indices of the unique values in the original array, as well as the values themselves. If you only need the count of unique values, you can simply discard the indices output by unique.