如何在python中使用for循环从字符串中打印每个唯一单词的频率

Question

该段落旨在包含空格和随机标点符号，我通过执行 .replace 在 for 循环中删除了它们。然后我通过 .split() 将段落放入一个列表中以获得 ['the', 'title', 'etc']。然后我做了两个函数 count words 来计算每个单词，但我不想它计算每个单词，所以我做了另一个函数来创建一个唯一的列表。但是，我需要创建一个 for 循环来打印出每个单词以及它被说了多少次，输出是这样的

The word The appears 2 times in the paragraph.

The word titled appears 1 times in the paragraph.

The word track appears 1 times in the paragraph.

我也很难理解 for 循环的本质。我读到我们应该只使用 for 循环进行计数，而 while 循环可以用于其他任何事情，但 while 循环也可以用于计数。

    paragraph = """  The titled track “Heart Attack” does not interpret the 

    feelings of being in love in a serious way, 

    but with Chuu’s own adorable emoticon like ways. The music video has 

    references to historical and fictional 

    figures such as the artist Rene Magritte!!....  """

for r in ((",", ""), ("!", ""), (".", ""), ("  ", "")):

    paragraph = paragraph.replace(*r)

paragraph_list = paragraph.split()

def count_words(word, word_list):

    word_count = 0

    for i in range(len(word_list)):

        if word_list[i] == word:

            word_count += 1

    return word_count

def unique(word):

    result = []

    for f in word:

        if f not in result:

            result.append(f)

    return result

unique_list = unique(paragraph_list)

Answer 1

请注意，您的示例文本很简单，但标点规则可能很复杂或未正确遵守。包含 2 个相邻空格的文本是什么（是的，它不正确但很频繁）？如果作者更习惯法语并在冒号或分号前后写空格怎么办？我认为's构造需要特殊处理。怎么样："""John has a bicycle. Mary says that her one is nicer that John's."""恕我直言，这个词John在这里出现了两次，而你的算法会看到 1John和 1 Johns。此外，由于 Unicode 文本现在在 WEB 页面上很常见，您应该准备好找到空格和标点符号的高代码等效项：“ U+201C LEFT DOUBLE QUOTATION MARK” U+201D RIGHT DOUBLE QUOTATION MARK’ U+2019 RIGHT SINGLE QUOTATION MARK‘ U+2018 LEFT SINGLE QUOTATION MARK  U+00A0 NO-BREAK SPACE此外，根据这个较旧的问题，删除标点符号的最佳方法是translate. 链接问题使用 Python 2 语法，但在 Python 3 中您可以执行以下操作：paragraph = paragraph.strip()                   # remove initial and terminal white spacesparagraph = paragraph.translate(str.maketrans('“”’‘\xa0', '""\'\' '))  # fix high code punctuationsparagraph = re.replace("\w's\s", "", paragraph)  # remove 'sparagraph = paragraph.translate(str.maketrans(None, None, string.punctuation) # remove punctuationswords = paragraph.split()