How do I pick a value in a matrix of characters?

I need to do something that is similar to what is seen here: http://www.mathworks.com/matlabcentral/answers/203608-how-to-pick-values-that-is-below-a-certain-value-in-a-matrix-vector

I generated a matrix by the following:

field = ones(height,width) .* 'O';

field = char(field);

And then I have some code to have a M in the top left field and another spot that varies depending on user input. I need to be able to select just the values of the field that are 'M'

[Image Analyst]

"I need to be able to select just the values of the field that are 'M'" <== wouldn't those just simply have values of 'M'????

Answer 1

[Image Analyst]

Assuming you mean the "locations" rather than "values" of the M's, try this:

height = 6;
width = 3;
field = ones(height,width) .* 'O';
field = char(field)
field(2, 3) = 'M';
field(4, 1) = 'M';
[rows, columns] = find(field == 'M')

[Alec Gutmanstein]

You assumed correct. I have to be able to control/manipulate the location of M's. This should do the trick. Thanks!