Python Mad Libs项目问题：用户输入无法替换占位符并保存

问题场景 #

用Python开发Mad Libs风格项目，收集VERB_ING、NOUN、ADJECTIVE等用户输入替换文本占位符，但运行程序后，原文件里的占位符未被替换，怀疑save_crazy_lib函数存在bug。

终端操作步骤 #

michaelsmacbook@Michaelss-MBP Desktop % python3 crazy.py lib.txt 
Enter a VERB_ING:drink    
Enter a NOUN:water 
Enter a VERB_ING:go 
Enter a ADJECTIVE:quickly 
Enter a NOUN:north 
Enter a VERB_ING:smiling
Enter a NOUN:goth

michaelsmacbook@Michaelss-MBP Desktop % cat lib.txt

原始lib.txt文本 #

The first thing that stands between you and VERB_ING your first,
real, piece of NOUN, is VERB_ING the skill of breaking problems down
into achievable ADJECTIVE actions that a NOUN can do for you. Of
course, you and the computer will also need to be VERB_ING a common
NOUN, but we'll get to that topic in just a bit.

完整代码 #

import sys

def make_crazy_lib(filename):
    try: 
        file = open(filename, 'r')
        text = ''

        for line in file:
            text = text + process_line(line)
        file.close()

        return text
    except FileNotFoundError:
        print("Sorry, cound't find" + filename + '.')
    except IsADirectoryError:
        print("Sorry", filename, 'is a directory.')
    except:
        print("Sorry, could not read", filename)

placeholders = ['NOUN', 'ADJECTIVE', 'VERB_ING','VERB']

def process_line(line):
    global placeholders
    processed_line = ''

    words = line.split()

    for word in words:
        stripped = word.strip('.,:?!')
        if stripped in placeholders:
            answer = input('Enter a ' + stripped + ":")
            processed_line = processed_line + answer 
            if word[-1] in '.,;?!':
                processed_line = processed_line + word[-1] + ' '
            else:
                processed_line = processed_line + ' ' 
        else:
            processed_line = processed_line + word + ' ' 

    return processed_line + '\n'

def save_crazy_lib(filename, text): #This may be where the issue is
    try:
        file = open(filename, "w")
        file.write(text)
        file.close()
    except:
        print("Sorry, couldn't write file." + filename, lib)


def main():
    if len(sys.argv) != 2:
        print("crazy.py<filename>")
    else:
        filename = sys.argv[1]
        lib = make_crazy_lib(filename)
        if (lib != None):
            save_crazy_lib('crazy' + filename, lib)

if __name__ == '__main__':
    main()

问题分析与修复 #

1. 核心误解：保存路径错误
   代码中main函数调用save_crazy_lib时，传入的文件名是'crazy' + filename，也就是输入lib.txt时，替换后的内容会保存到crazylib.txt，而非原lib.txt。你运行cat lib.txt查看的是未修改的原文件，自然看不到替换结果。

2. save_crazy_lib函数的异常处理bug
   异常提示中使用了未定义的变量lib，修正后的函数如下：

   def save_crazy_lib(filename, text):
       try:
           file = open(filename, "w")
           file.write(text)
           file.close()
       except Exception as e:
           print(f"Sorry, couldn't write file {filename}: {e}")
   

3. 可选：覆盖原文件
   如果需要直接替换原文件内容，将main函数中的调用改为：

   save_crazy_lib(filename, lib)
   

4. 其他小问题修正
   make_crazy_lib函数中的拼写错误：cound't改为couldn't。

验证方法 #

• 若保留原保存路径，运行程序后查看crazylib.txt即可看到替换后的内容；
• 若修改为覆盖原文件，直接运行cat lib.txt就能验证结果。

内容的提问来源于stack exchange，提问作者Michael Agunga