Question

我在python中有以下列表

texts = [
    ["great", "even", "for", "the", "non", "runner", "this", "sound",
     "track", "was", "brilliant"],
    ["cannot", "recommend", "as", "a", "former", "comrade", "i", "did",
     "not", "want", "to", "have", "to", "do", "this"]
]

我想浏览一下列表并计算每个单词出现在列表中的频率。

我尝试使用length()对单个单词进行计数，结果得到2，这意味着它不起作用。

有什么方法可以计算一个单词在列表中出现的频率，因为我打算将计数的单词存储在一个新列表中，并将其频率存储在另一个列表中。

预先感谢

Answer 1

要注意的第一件事可能是texts是一个嵌套列表，这也是为什么2包含len(texts)包含2个子列表的原因，而为texts得到[word for words in texts for word in words]的原因。

如果要遍历各个单词，则需要遍历子列表，然后遍历子列表中的单词。幸运的是，Python的列表推导可以嵌套：

word_counts = collections.Counter(word for words in texts for word in words)

关于计数：标准库中有一个专门用于此类目的的字典类：collections.Counter：

{{1}}

这将为您提供一个字典，将各个单词映射到它们的出现次数。

Answer 2

您可以为此使用Counter。

texts = [
    ["great", "even", "for", "the", "non", "runner", "this", "sound",
      "track", "was", "brilliant"],
    ["cannot", "recommend", "as", "a", "former", "comrade", "i", "did",
      "not", "want", "to", "have", "to", "do", "this"]
]

for text in texts:
    cnt = Counter()
    for word in text:
        cnt[word] += 1
    print(cnt)

Answer 3

一个班轮：

from collections import Counter
from itertools import chain

texts = [["a", "b"], ["a", "c"]]

words_count = Counter(chain(*texts))
print(words_count)

>> Counter({'a': 2, 'b': 1, 'c': 1})

Answer 4

您可以使用Counter来计算单词数：

from collections import Counter

texts = [["great", "even", "for", "the", "non", "runner", "this", "sound","track", "was", "brilliant"],
         ["cannot", "recommend", "as", "a", "former", "comrade", "i", "did", "not", "want", "to", "have", "to", "do", "this"]]

for text in texts:
    print(Counter(text))

# Counter({'great': 1, 'even': 1, 'for': 1, 'the': 1, 'non': 1, 'runner': 1, 'this': 1, 'sound': 1, 'track': 1, 'was': 1, 'brilliant': 1})
# Counter({'to': 2, 'cannot': 1, 'recommend': 1, 'as': 1, 'a': 1, 'former': 1, 'comrade': 1, 'i': 1, 'did': 1, 'not': 1, 'want': 1, 'have': 1, 'do': 1, 'this': 1})

来源：How do I count unique values inside a list

如何计算一个单词在python列表中出现多少次

4 个答案: