How to create a histogram with weighted values from an array?

Hi all,

I am relatively new to MatLab so I need some assistance with this task. Basically, I have two arrays that I want to weigh the other with and create an overall histogram. To explain this better, I have an array that contains the bins (A) and an array with weighted values (B):

A = [70 90 80; 90 90 90; 80 60 70]

B = [0.5 0.8 1.0; 0.2 0.5 1.0; 0.3 0.2 0.5]

Ultimately, I want my bin counts to be:

60 bin: 0.2 70 bin: 1.0 80 bin: 1.3 90 bin: 2.5

Is there a way to use the A array to classify the weighted counts of array B and create a histogram?

Thanks in advance!

Answer 1

[Alan Stevens]

This will do it (though there might well be a neater way!):

A = [70 90 80; 90 90 90; 80 60 70];
B = [0.5 0.8 1.0; 0.2 0.5 1.0; 0.3 0.2 0.5];
A = A(:); B = B(:); C = sortrows([A B]);
k = 0;
for i = 60:10:90
    ix = C(:,1)==i;
    k = k+1;
    bin(k) = sum(C(ix,2));
    ix = [];
end

[DL]

Thank you Alan! This works perfectly.

[Vlatko Milic]

Hi,

How do you get the histogram after the for-loop? With the bin properties you stated before? I tried the same procedure but could not get the correct histogram...