Count values in an array if the sum of the values exceeds a certain number

I am a beginner in MATLAB. I have an array of [0.55, 0.4, 0.55], and I would like to count the how many values should be included to exceed a certain number (0.9 for example).

 x=  0.5500
    0.4000
    0.0500

I would like the output to be:

 y= 2

Because the sum of the first two values are already greater than 0.9, there is no need to include the third number.

This is the situation of three numbers, I would also want to see how this can work for a list of more than three values.

Thanks!

Answer 1

[aborghes]

probably not the most elegant, but this seems to work:

x = [.55, .4, .05, .5, .9]
num = 0
val = .9
for y=1:length(x)
    if(num<val)
        num = num+x(i)
    else
        y = y-1;
        break
    end
end
y

the value of why at the end will give you the result you are looking for

[Xiaochen Sun]

Thanks! I finally find a way to do this...

 x = [.55, .4, .05, .5, .9]
 x=sort(x,'descend')
 cumx=cumsum(x)
 n=find(cumx>=0.9,1)

This works for me now. But thank you for your reply!