MATLAB: Extracting data from matrix: newbie question

matrix

I am new to matlab.
I am trying to use matlab for a psychology experiment. I obtained data in a matrix with two columns. The first column refers to the distance in cm and the second column to reaction time. The data matrix that I have looks something like this:
distance = [ 0.1 0.332;
             0.2 0.678;
             0.1 0.876;
             0.3 0.765;
             0   0.345;
             0.2 0.541;
             0.3 0.541;
             0.1 0.567;
             0.2 0.123;]
The distance (column 1) can be 0, 0.1, 0.2 or 0.3. I would like separate matrices for each of these distances (so I can compare their reaction times).
I wrote a for loop
S = 1;
T = 1;
U = 1;
V = 1;
for F = 1:length(distance)
    if      distance(F,1) == 0
            distance_0(S,1) = distance(F,2);
            S = S + 1;
    elseif distance(F,1) == 0.1
            distance_1(T) = distance(F,2);
            T = T + 1;   
    elseif distance(F,1) == 0.2
            distance_2(U) = distance(F,2);
            U = U + 1;
    else    distance(F,1) == 0.3
            distance_3(V) = distance(F,2);
            V = V + 1;
    end
end
The output should look like this:
distance_0  = [0.345]
distance_1 = [0.332; 0.876; 0.567]
distance_2 = [0.678; 0.541; 0.123]
distance_3 = [0.765; 0.541]
However, it is not working well and I don' t get the above output matrices. The matrices distance_* are only filled partly. What am I doing wrong! I hope someone can help me. Thanks in advance.

Best Answer

clear
distance = [ 0.1 0.332;
             0.2 0.678;
             0.1 0.876;
             0.3 0.765;
             0   0.345;
             0.2 0.541;
             0.3 0.541;
             0.1 0.567;
             0.2 0.123;];
%---------- ------------------------------------------------
n=size(distance,1);
S = 1;
T = 1;
U = 1;
V = 1;
for F = 1:n
  if distance(F,1) == 0
      distance_0(S,1) = distance(F,2);
      S = S + 1;
  elseif distance(F,1) == 0.1
      distance_1(T) = distance(F,2);
      T = T + 1;
  elseif distance(F,1) == 0.2
      distance_2(U) = distance(F,2);
      U = U + 1;
  elseif  distance(F,1) == 0.3
      distance_3(V) = distance(F,2);
      V = V + 1;
  end
end
disp(distance_0)
disp(distance_1)
disp(distance_2)
disp(distance_3)
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