Python - 返回频率最高的前 5 个单词

Question

正如标题所说，我需要编写一个代码来返回频率最高的 5 个单词（来自输入字符串）的列表。这是我目前所拥有的：

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，如果你输入：top5_words("one one was a racehorse two two is one too") 它应该返回：["one", "two", "was", "a", "racehorse"] 但是而是返回：['one', 'was', 'two', 'racehorse', 'too', 'a'] - 有人知道这是为什么吗？

编辑：

感谢 Anand S Kumar，这就是我现在所拥有的：

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

你应该使用 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 count ，那么您还可以使用列表推导来获取该信息。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']

---

对于来自 cmets 的新要求 -

对于频率相同的单词似乎仍然存在问题，我如何让它按字母顺序对频率相同的单词进行排序？

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 sorted 首先对计数进行排序，然后对元素本身进行排序（因此当计数相同时，它会按字典顺序排序）。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']