to retrieve data from a n*n matrix

hi i have x=[2 4 2 6 1;4 3 6 3 3; 2 5 6 4 1;3 4 5 2 2;3 5 2 6 3]

the first four coloumns represents bins 1 to 6 and the 5th column represents the class

a) i want to know the no of elements present in each bin based on the data given in first four columns as a row vector of size 1*6 the answer must be[0 5 4 4 3 4]

b)i want to get 3 different matrices based on the class that is the fifth column

answer: class1=[2 4 2 6 1;2 5 6 4 1] class2=[3 4 5 2 2] class3=[4 3 6 3 3;3 5 2 6 3]

Thanks in advance

Answer 1

[Oleg Komarov]

a)

data = x(:,1:end-1);
histc(data(:),1:max(data(:))).'

b) Why would you want to separate it when yuo can index it?

class1 = x(x(:,end) == 1,:);
class2 = x(x(:,end) == 2,:);
class3 = x(x(:,end) == 3,:);

[bilhan]

Thank you Mr.Komarov