How do I sum the count between two values in an array corresponding to the values in another array of the same length?

Hi,

I have very long text files of data that when loaded into matlab give me two arrays - each bin corresponding to a value in another:

    e.g

    x-data    y-data

    1392.6    8000

    1392.9    8500

    1393.1    8900

    1393.4    9500

    1394.2    10000

    1394.6    10002

    1394.9    15000

    1395.2    17500

    1395.5    15000

    1396.4    10000 

    1397.1    8000

And I want to know what the sum of the y values between x = 1393 to 1396 is. E.g

some funtion that searches x array for values between 1393 and 1396 and sums the corresponding y values

therefore answer for above data would be 85,902.

Any ideas? I'm new to matlab so bear with me!

Thank you,

PC

Answer 1

[Guillaume]

Use find to get the indices of x that are within the range you want, and use these indices to get the elements of y:

sum(y(find(x >= 1393 & x <= 1396)))

[Paul Clarkson]

Thank you Guillaume!