Is there a faster way to change zeros to ones and ones to zeros?

Right now for a 100x100x3 uint8 matrix, this is what I have:

       for f = 1:100
            for g = 1:100
                for h = 1:3
                    if gMaster(f, g, h) == 0
                        gMaster(f, g, h) = 1;
                    elseif gMaster(f, g, h) == 1
                        gMaster(f, g, h) = 0;
                    end
                end
            end
        end

But it takes a long time to iterate through the array. Is there a faster way to do this?

Answer 1

[jonas]

You can do

A = ~A

however it returns a logical, so if you want a uint8 you have to:

A = uint8(~A)

[Stephen23]

A simple way to ensure the output has the same class as the input:

A(:) = ~A

And of course it is important to note that using negation converts all non-zero values to zero, and all zeros to one, so it is not exactly equivalent to the code shown in the question: to get the exact equivalent, you would need to add some simple indexing.

Answer 2

[James Tursa]

Assuming you have only 0's and 1's in your array, here is another way that also keeps the class of the result as uint8:

A = 1 - A;

This seems to be faster than the other methods proposed.

[Stephen23]

"This seems to be faster than the other methods proposed."

Changing class twice is going to be slow, so no surprises there.