从包含浮点数和字符串的列表中打印浮点数的平均值

Question

I'm performing sentiment analysis on Tweets I've collected, and each outcome looks like this, depending on the amount of tweets:

['pos', 0.8, 'neg', 1.0, 'pos', 1.0, 'pos', 1.0, 'pos', 1.0, 'pos', 1.0, 'neg', 1.0]  

The floats stand for the confidence%, and I want to calculate & print the average of all of them from this list, but I'm having quite some trouble with it.

Answer 1

This is one way:

A = ['pos', 0.8, 'neg', 1.0, 'pos', 1.0, 'pos', 1.0, 'pos', 1.0, 'pos', 1.0, 'neg', 1.0]  

res = sum(A[1::2]) / (len(A) / 2)

print(res)

0.9714285714285714

Or if you would rather not create a new list:

from itertools import islice

res = sum(islice(A, 1, None, 2)) / (len(A) / 2)

Alternatively, you can use statistics.mean , also in the standard library:

from statistics import mean

res = mean(A[1::2])