Is there any pythonic way to find average of specific tuple elements in array?

I want to write this code as pythonic. My real array much bigger than this example.

( 5+10+20+3+2 ) / 5

print(np.mean(array,key=lambda x:x[1])) TypeError: mean() got an unexpected keyword argument 'key'

array = [('a', 5) , ('b', 10), ('c', 20), ('d', 3), ('e', 2)]
sum = 0

for i in range(len(array)):

sum = sum + array[i][1]
average = sum / len(array)

print(average)
import numpy as np

print(np.mean(array,key=lambda x:x[1]))

How can avoid this? I want to use second example.

#python #arrays