Controlling a servo with a output from a cell array

I have a 1x28 cell array that has a bunch of letters in it. I need to pull from each column, and if the letter is this, a certain servo would do that.

For example

%cell array output
R(:,1) = {'U'}

%'U' would turn the top servo 90 degrees, 50 steps

Im new to the matlab arduino library, so not sure how to do this