Obtaining how many times a number is repeated (Matlab)

Dear members;

I have vector S=[0 1 1 0 1] in which the position L of ones is

L=find(S==1); So L=[2,3,5]

I have also Bi (i=1:5) in each Bi I have the position of ones like this :

B1=[1,2,5,6,7,8] B2=[1,3,4,6,8,10] B3=[2,4,5,8,9,10] B4=[1,3,5,7,9,10] B5=[2,3,4,6,7,9]

Because L=[2,3,5] I have to go to B2, B3 and B5 and obtaining how many times each number from 1 to 10 is repeated

For example from B2, B3 and B5 (number 1 is repeated just once in B2) and (number 2 is repeated twice in B3 and B5), (number 3 is repeated twice in B2 and B5), (number 4 is repeated thrice in B2, B3 and B5) .... etc until number 10.

So please help me how can I program this in Matlab

Thank you

[KSSV]

Read about unique and hist.

Answer 1

[Jan]

Do not use indices hidden in the name of the variables, but indices of arrays:

B{1} = [1,2,5,6,7,8];
B{2} = [1,3,4,6,8,10];
B{3} = [2,4,5,8,9,10];
B{4} = [1,3,5,7,9,10];
B{5} = [2,3,4,6,7,9];
S    = [0 1 1 0 1];

BS = cat(2, BS{S == 1});
D  = histcounts(BS, 'BinMethod', 'integers')

[Afluo Raoual]

But what if I want use for loop ?

Because I make a loop that give at each time values of Bi, that's why.

H=[1 1 0 0 1 1 1 1 0 0;

1 0 1 1 0 1 0 1 0 1;

0 1 0 1 1 0 0 1 1 1;

1 0 1 0 1 0 1 0 1 1;

0 1 1 1 0 1 1 0 1 0];

[M N]=size(H);

S=[0 1 1 0 1];

L=find(S==1);

for i = 1:M

Bi = find(H(i,:));

end

But how to add your program then to this one please

[Rik]

Then you can do this:

B{1} = [1,2,5,6,7,8];
B{2} = [1,3,4,6,8,10];
B{3} = [2,4,5,8,9,10];
B{4} = [1,3,5,7,9,10];
B{5} = [2,3,4,6,7,9];
S    = [0 1 1 0 1];

for I_am_a_useless_variable=1
    BS = cat(2, BS{S == 1});
    D  = histcounts(BS, 'BinMethod', 'integers')
end

If you're required to use a loop because this is homework you can still try my suggestion. Otherwise you can find guidelines for posting homework on this forum here.

[Jan]

@Afluo Raoual: Now your input look different.

H =  [1 1 0 0 1 1 1 1 0 0;
      1 0 1 1 0 1 0 1 0 1;
      0 1 0 1 1 0 0 1 1 1;
      1 0 1 0 1 0 1 0 1 1;
      0 1 1 1 0 1 1 0 1 0];
S = [0 1 1 0 1];
B = sum(H(S == 1, :), 1);

Why do you want to waste time with a loop? Do you really need the indices obtained by FIND?

[Afluo Raoual]

Thank you so much. It works now with this simple idea. I thought it can just solved with for loop.

I appreciate your help as always.