# 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;    endend
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.

• cleardistance = [ 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;  endenddisp(distance_0)disp(distance_1)disp(distance_2)disp(distance_3)