在字符串 Python 中查找数组的平均长度

Question

I am a student VERY new to python and I have no idea how to write a function that calculates the mean length of an array in a string. Any help or guidance would be greatly appreciated. We are given

def mean_length(lst):

The tests are

assert mean_length(['fee','freed',free']) == 4
assert mean_length(['alpha', 'beta', 'gamma', 'delta', 'epsilon']) == 5.2
assert mean_length([]) == 0

I have tried

def mean_length(lst):
    x = lst.count(''.join(lst))
    y = int(3)
    mean = x / y
    return mean

Answer 1

There's already a function in the statistics library that can do this just map len to the list so you supply it the lengths.

l = ['fee','freed','free']
statistics.mean(map(len, l))

Answer 2

The answer is just a one-liner:

def mean_length(l):
    return len(''.join(l))/len(l)

Here we are joining all the string in the list and counting the total number of characters and finally dividing it by the total number of elements in the list , thereby, giving us mean length of words.