如何从列表中选择值？

Question

我想选择末尾带有标签“ 1”的值，并从所选值中随机选择1000条注释。

这是在上面创建输出的代码的文本版本：

with open('movie_ratings.txt', 'r') as f:
    lines = f.read().splitlines()
lines = lines[1:]

sentences = [line.split('\t') for line in lines]
sentences

Answer 1

仅选择最后一个元素为“ 1”的句子：

sentences = [line.split('\t') for line in lines if line.split('\t')[-1] == '1']

对于随机选择，这可以帮助您： Python random.choice() function to select random item from a List and Set

Answer 2

首先加载行

lines = open('movie_ratings.txt').read().splitlines()[1:]
sentences = [line.split('\t') for line in lines]

现在，我们将注释的最后一个值保留为'1'

comments_to_keep = [
    comment for rating_id, comment, flag in sentences
    if flag == '1'
]

现在我们对这些评论进行抽样

import random
sample = random.sample(comments_to_keep, 1000)