如何计算一个单词在文件行中的出现次数？

Question

我有以下问题。在我的初级Python课程中，期中考试就要到了，虽然我理解了练习期中的其他问题，但这一次让我有点难堪。首先，这是问题的文本。我遇到的麻烦是如何遍历一行中的每个单词，并检查它是否已经被看到。我觉得很难概念化。首先，以下是问题的文本：

Write a function named cloneLines that takes two parameters:
1. inFile, a string, the name of an input file that exists before cloneLines is called
2. outFile, a string, the name of an output file that cloneLines creates and writes to

函数cloneLines逐行读取inFile的内容，并将至少包含一个在该行中出现多次的单词的任何行写入outFile。您可以假设输入文件只包含小写字母、空格和换行符。你知道吗

例如，如果以下是文件william.txt的内容：

double double toil and trouble
fire burn and caldron bubble
eye of newt and toe of frog
fillet of a fenny snake
in the caldron boil and bake
double double toil and trouble
fire burn and caldron bubble

以下函数调用：

inFile = 'william.txt'
outFile = 'clones.txt'
cloneLines(inFile, outFile)

应创建包含以下内容的文件clones.txt：

double double toil and trouble
eye of newt and toe of frog
double double toil and trouble

我只需要打开文件进行读写，然后开始for循环。再说一次，我很难理解这个。任何额外阅读的建议都会非常有用。我应该把从文件中读入的行分开吗？我只需要被指向一个大致的方向。你知道吗

def cloneLines (inFile, outFile):
    inputfile = open(infile)
    outputfile = open(outfile, 'w')

    for line in inputfile.read():
        ...

Answer 1

以下内容将写入输出文件，即在该行中多次包含同一单词的任何行。你知道吗

import sys

class SplitStream:
    """
    This is just so you can see the contents
    of the output file
    without having to open the output file
    """
    def __init__(self, s1, s2):
        self.s1 = s1
        self.s2 = s2
    def write(self, arg):
        self.s1.write(arg)
        self.s2.write(arg)


def cloneLines(inFile:str, outFile:str):
    inFile  = str(inFile)
    outFile = str(outFile)
    with open(inFile , mode = "r") as i_f:
        with open(outFile, mode="w") as o_f:
            o_f = SplitStream(o_f, sys.stdout)
            # TODO remove `SplitStream`
            for line in i_f:
                if contains_a_word_more_than_once(line):
                    o_f.write(line)

def contains_a_word_more_than_once(stryng):
    stryng = str(stryng)
    sep_words = stryng.split(" ")

    # if `stryng` is...
    #     "fillet of a fenny snake"
    #
    # then `sep_words` is:
    #     ["fillet", "of", "a", "fenny", "snake"]

    d = dict()    
    for word in sep_words:
        if word in d.keys():
            return True
        d[word] = True
    return False