henrik.py

import numpy as np

x = np.array([500, 500, 500, 1000, 1000, 1000, 1500])
y = np.array([1,2,3,4,5,6,7])

data = np.stack([x,y]).T

means = []
stds = []
for xi in np.unique(data[:,0]):
    mask = data[:,0] == xi
    vals = data[:,1][mask]
    means.append(vals.mean())
    stds.append(vals.std())
    
means = np.array(means)
stds = np.array(stds)


means

stds