从一个文件的特定索引中复制字符串，将该字符串粘贴到另一个文件中的特定位置

Question

我的意图是在文件1的冒号或等号之后复制一段字符串，并将该字符串粘贴到文件2中在冒号或等号后​​的相似位置。

例如，如果文件1有： 用户名：堆栈

文件2原本是空的： 用户名=

我想栈能够复制的用户名后，文件2。目前，我卡住了，不知道该怎么做。我在下面制作的程序片段不会复制用户名。我将非常感谢任何输入！

with open("C:/Users/SO//Downloads//f1.txt", "r") as f1: 
    with open("C:/Users/SO//Downloads//f2.txt", "r+") as f2: 
     searchlines = f1.readlines() 
     searchlines_f2=f2.readlines()   
     for i, line in enumerate(searchlines): 
      if 'username' in line: 
       for l in searchlines[i:i+1]: 
        ind = max(l.find(':'), l.find('='), 0) #finding index of specific characters 
        copy_string=l[ind+1:].strip() #copying string for file 2 
        for l in searchlines_f2[i:i+1]: 
         if 'username' in line: 
          f2.write(copy_string) 

Answer 1

我觉得像这样的东西会让你得到你需要的更多维护和Pythonic的方式。

注意使用正则表达式以及一些字符串方法（例如，startswith）

import re 

SOURCE_PATH = "C:/Users/SO//Downloads//f1.txt" 
TARGET_PATH = "C:/Users/SO//Downloads//f2.txt" 

def _get_lines(filepath): 
    """ read `filepath` and return a list of strings """ 
    with open(filepath, "r+") as fh: 
     return fh.readlines()  

def _get_value(fieldname, text): 
    """ parse `text` to get the value of `fieldname` """ 
    try: 
     pattern = '%s[:=]{1}\s?(.*)' % fieldname 
     return re.match(pattern, text).group(1) 
    except IndexError: 
     # you may want to handle this differently! 
     return None 

def _write_target(filepath, trgt_lines): 
    """ write `trgt_lines` to `filepath` """ 
    with open(filepath, "w+") as fh: 
     fh.writelines(trgt_lines) 

src_lines = _get_lines(SOURCE_PATH) 
trgt_lines = _get_lines(TARGET_PATH) 

# extract field values from source file 
fields = ['username', 'id', 'location'] 
for field in fields: 
    value = None 
    for cur_src in src_lines: 
     if cur_src.startswith(field): 
      value = _get_value(field, cur_src) 
      break 

    # update target_file w/ value (if we were able to find it) 
    if value is not None: 
     for i, cur_trgt in enumerate(trgt_lines): 
      if cur_trgt.startswith('{0}='.format(field)): 
       trgt_lines[i] = '{0}={1}'.format(field, value) 
       break 
_write_target(TARGET_PATH, trgt_lines)