Trying to bin one column and sum the other simultaneously. Please help.

[arick1234]

I have an array [x,y] where the values of x is ascending and the y values are random. I would like to sum all of the y values together when the x values are within a certain range. I can't show you any code as i dont even know where to start with this but this is the desired effect:-

Example data:-

(1, 0.5)
(2, 5.0)
(4, 2.0)
(7, 0.5)
(8, 0.5)
(10, 2.5)
(11, 1.5)
(15, 3.0)
(18, 4.0)
(20, 0.5)
...... etc.

If the range of y is 10. So from y=1 to y=10 and from y=11 to y=20 the x values will be summed within these two bands, I will get a list:-

11.0, 9.0, ...... etc.

So far I have been advised to sum all the y values, this gives:-

 SELECT ALL
import numpy, scipy, matplotlib.pylab as plt

mjd1, flux1, error1 = numpy.loadtxt("log_207_band1.dat", usecols=(1,2,3), unpack=True)

x=mjd1
y=flux1
z=zip(x,y)

print sum(i[1] for i in z)

I'm really at a loss of what to do next.

Thanks.

[Glenton]

I'd define my bins first:
Eg bin=range(10,10 0,10)

Then make you list of sums:
Sums=[0]

Then loop through either adding the y value to the last value (ie Sums[-1]) or appending a new value to Sums (ie Sums.append(0)) according to the value of x.

[Glenton]

bin=10
sums=[0]
for x,y in zip(xs,ys):
    if x>bin:
        bin+=10
        sums.append(0)
    sums[-1]+=y

Should do it.