如何停止遍历枚举列表的循环？

问题描述

我已开始使用 Python 中的 enumerate() 函数，并希望改进我在 this Stackoverflow post 中首次讨论的关键字上下文脚本。

由于初始脚本仅检索每个关键字的第一个实例及其后续单词，因此我尝试编写一个脚本来遍历整个文件并将所有单词与关键字列表进行比较。

然而，发生的情况是，我得到了一个我的 Jupyter Notebook 无法处理的所谓无休止的结果列表。我什至尝试在枚举 break 大于分析的文本文件中的单词数时立即用 i 强制停止。不幸的是，这也不起作用。

我想我还没有完全掌握 enumerate() 函数背后的逻辑，希望得到您的建议。

这是我的当前脚本：

# Find keywords and "n" subsequent words in txt file
# credits to @jasonharper and @xander for prevIoUs updates
# cf. forum discussion on https://stackoverflow.com/questions/66972612/how-to-match-value-in-enumeration-to-a-keyword

import string

# function to find keywords in context
def wordsafter(keyword,source):
        wordcount=len(source) # sample text has 5953 words in total
        print(wordcount)
        res_strings=[]    
        for i in range(0,wordcount):
            if i < wordcount:
                print(i) # prints correct range from 0 to 5952
                for i,val in enumerate(source):
                    if val == keyword:
                        res_str=(' '.join(source[i:i + 10]))  # show searchterm and subsequent n words
                        res_strings.append(res_str)
            if i > wordcount:
                break # how can I force function to check each word only once?
            
        return(res_strings) # returns endless (?) list of results?
    
# open input txt file from local path
with open('C:\\somefile.txt','r',encoding='utf-8',errors='ignore') as f:  # open file
    data1 = f.read()  # read content of file as string
    data2 = data1.translate(str.maketrans('','',string.punctuation)).lower()  # remove punctuation
    data3 = " ".join(data2.split())  # remove additional whitespace from text
    indata = list(data3.split())  # convert string to list

# define searchterms and call function    
searchterms = ["proclamation"] 
for keyword in searchterms:
    result = wordsafter(keyword,indata)
    if result:
        print(result[600000]) # prints a valid string although whole file only has 5953 items
        with open('C:\\Users\\anotherfile.txt','w',encoding="utf-8-sig") as file:
            file.write(str(result)) # output file is so large it crashes when opened

解决方法

不确定发生了什么，但在另一台机器上运行原始脚本会产生完全正确的输出，不需要强制中断：

# Find keywords and five subsequent words
# Updated script with credits to @jasonharper and @xander
# cf. forum discussion on https://stackoverflow.com/questions/66972612/how-to-match-value-in-enumeration-to-a-keyword

import string

# function to find keywords in context
def wordsafter(keyword,source):
        wordcount=len(source) # shows number of words in sample text
        print(wordcount)
        res_strings=[]    
        for i,val in enumerate(source):
            if val == keyword:
                res_str=(' '.join(source[i:i + 10]))  # shows searchterm and subsequent "n" words
                res_strings.append(res_str)
            
        return(res_strings) # returns list of results
    
# open input txt file from local path
with open('C:\\Users\\input.txt','r',encoding='utf-8',errors='ignore') as f:  # open file
    data1 = f.read()  # read content of file as string
    data2 = data1.translate(str.maketrans('','',string.punctuation)).lower()  # remove punctuation
    data3 = " ".join(data2.split())  # remove additional whitespace from text
    indata = list(data3.split())  # convert string to list

# define searchterms and call function    
searchterms = ["proclamation","king"] 
for keyword in searchterms:
    result = wordsafter(keyword,indata)
    if result:
        print(result) 
        with open('C:\\Users\\output.txt','w',encoding="utf-8-sig") as file:
            file.write(str(result)) # write output to file

enumeration loops python