Python finds the mean, variance and label difference of a series

1. Find the mean:

import numpy as np
from time import time

a = list(range(1, 100000))
mean1 = np.mean(a)  # method 1
mean2 = sum(a) / len(a)  # method 2

From the time-consuming point of view, np.mean() will take longer than the second method . Therefore, it is not recommended to use the np module for averaging .

2. Find the variance:

When you look at the formula of variance, you know that you have to add a for loop to write it, so the np module is recommended here

import numpy as np
from time import time

a = list(range(1, 100000))
s2 = np.var(a)

You can find the variance directly with np.var() .

3. Find the difference:

This can be done directly, and np.std() can also be used .