如何避免双重搜索和替换

Question

我有以下代码： 我需要通过在开头放置 # 来删除一行。它很好用。 问题是如果该行已经被# 注释掉，并且再次运行查询。它在行中放置第二个#。在实际文件“getweather.sh”中，我得到了一行看起来像的行。如何搜索准确的文本？

####home/pi/allsky/get-temp.py

# Read in the file
with open('/home/pi/allsky/getweather.sh', 'r') as file :
  filedata = file.read()
# Replace the target string
filedata = filedata.replace('/home/pi/allsky/get-temp.py', '#/home/pi/allsky/get-temp.py')
# Write the file out again
with open('/home/pi/allsky/getweather.sh', 'w') as file:
  file.write(filedata)

Answer 1

我认为将整个文件作为单个字符串读取是错误的方法；您可以通过调用

readlines()

以字符串数组的形式读取文件（每行文本一个字符串）并逐行处理它来更轻松地获得您想要的行为，如下所示：

filePath = '/home/pi/allsky/getweather.sh'

# Read all lines of the file into an array of strings
with open(filePath, 'r') as inFile :
   inputLines = inFile.readlines()

# Write the array of strings back to the file, with # modification
with open(filePath, 'w') as outFile:
   for line in inputLines:
      line = line.strip()  # remove carriage-return/newline from the end
      if (line == '/home/pi/allski/get-temp.py'):
         outFile.write('#')
      outFile.write(line)
      outFile.write('\n')