Python - 返回频率最高的前 5 个单词

Question

正如标题所示，我需要编写一个代码，返回频率最高的 5 个单词(来自输入字符串)的列表。这是我到目前为止所拥有的:

from collections import defaultdict

def top5_words(text):
  tally = defaultdict(int)
  words = text.split()

  for word in words:
    if word in tally:
      tally[word] += 1
    else:
      tally[word] = 1

  answer = sorted(tally, key=tally.get, reverse = True)

  return(answer)

例如，如果您输入:top5_words(“一个一是一匹赛马二二也是一”)它应该返回:[“一”，“二”，"is"，“一”，“赛马”]但是相反，它返回: ['one', 'was', 'two', 'racehorse', 'too', 'a'] - 有人知道这是为什么吗？

编辑:

这就是我现在所拥有的，感谢 Anand S Kumar:

import collections

def top5_words(text):

  counts =  collections.Counter(text.split())

  return [elem for elem, _ in sorted(counts.most_common(),key=lambda x:(-x[1], x[0]))[:5]]

Answer 1

您应该使用collections.Counter然后你可以使用它的方法 - most_common() 。示例-

import collections
def top5_words(text):
    counts = collections.Counter(text.split())
    return counts.most_common(5)

请注意，上面返回一个包含 5 个元组的列表，在每个元组中，第一个元素是实际单词，第二个元素是该单词的计数。

演示 -

>>> import collections
>>> def top5_words(text):
...     counts = collections.Counter(text.split())
...     return counts.most_common(5)
...
>>> top5_words("""As the title says, I need to write a code that returns a list of 5 words (from an input string) that have the highest frequency. This is what I have so far""")
[('that', 2), ('a', 2), ('I', 2), ('the', 2), ('have', 2)]

---

如果您只想要元素而不是计数，那么您还可以使用列表理解来获取该信息。示例-

import collections
def top5_words(text):
    counts = collections.Counter(text.split())
    return [elem for elem, _ in counts.most_common(5)]

演示 -

>>> import collections
>>> def top5_words(text):
...     counts = collections.Counter(text.split())
...     return [elem for elem, _ in counts.most_common(5)]
...
>>> top5_words("""As the title says, I need to write a code that returns a list of 5 words (from an input string) that have the highest frequency. This is what I have so far""")
['that', 'a', 'I', 'the', 'have']

---

对于评论中的新要求 -

it seems there's still an issue when it comes to words with the same frequency, how would I get it to sort same frequency words alphabetically?

您可以首先获取所有单词及其计数的列表，然后使用 sorted ，这样排序首先对计数进行排序，然后对元素本身进行排序(因此，当计数时，它会按字典顺序排序)是一样的)。示例-

import collections
def top5_words(text):
    counts = collections.Counter(text.lower().split())
    return [elem for elem, _ in sorted(counts.most_common(),key=lambda x:(-x[1], x[0]))[:5]]

演示 -

>>> import collections
>>> def top5_words(text):
...     counts = collections.Counter(text.lower().split())
...     return [elem for elem, _ in sorted(counts.most_common(),key=lambda x:(-x[1], x[0]))[:5]]
...
>>> top5_words("""As the title says, I need to write a code that returns a list of 5 words (from an input string) that have the highest frequency. This is what I have so far""")
['a', 'have', 'i', 'that', 'the']