import pandas as pd
 
# list  1
a = [2, 3, 2.7, 3.2, 4.1]
 
# list 2
b = [10, 14, 12, 15, 20]
 
# storing average of a
av_a = sum(a)/len(a)
 
# storing average of b
av_b = sum(b)/len(b)
 
# making series from list a
a = pd.Series(a)
 
# making series from list b
b = pd.Series(b)
    
# covariance through pandas method
covar = a.cov(b)
 
 
# finding covariance manually
def covarfn(a, b, av_a, av_b):
    cov = 0
 
    for i in range(0, len(a)):
        cov += (a[i] - av_a) * (b[i] - av_b)
    return (cov / (len(a)-1))
 
# calling function
cov = covarfn(a, b, av_a, av_b)
 
# printing results
print("Results from Pandas method: ", covar)
print("Results from manual function method: ", cov)

Results from Pandas method:  2.8499999999999996
Results from manual function method:  2.8499999999999996