sort list of floating-point numbers in groups

Question

I have an array of floating-point numbers, which is unordered. I know that the values always fall around a few points, which are not known. For illustration, this list

Answer 1

You can try the following method:

Sort the array first, and use diff() to calculate the difference between two continuous values. the difference larger than threshold can be consider as the split position:

import numpy as np
x = [10.01,5.001,4.89,5.1,9.9,10.1,5.05,4.99]
x = np.sort(x)
th = 0.5
print [group.mean() for group in np.split(x, np.where(np.diff(x) > th)[0]+1)]

the result is:

[5.0061999999999998, 10.003333333333332]