Python 搜索行中的字符串

Question

我有以下代码，我认为它应该可以工作，但似乎没有：

old_name = 'Some User'
new_name = 'New User'

with open(complete_filename, 'r') as provisioning_file:
   lines = provisioning_file.read()
   # if the old_name is in this file
   if old_name in lines:
     file_found = 1
     with open(complete_filename + '.new', 'w') as new_provisioning_file:
       for line in lines:
         line = line.replace(old_name, new_name)
         new_provisioning_file.write(line)
         # provisioning_file.write(re.sub(old_name, new_name, line))

文件 complete_filename 将是各种配置文件，我一直在测试 XML 文件，其中一个示例片段如下：

  <reg reg.1.address="1234" reg.1.label="Some User" >
        <reg.1.auth reg.1.auth.password="XXXXXXXXXX" reg.1.auth.userId="1234" />
        <reg.1.outboundProxy reg.1.outboundProxy.address="sip.example.com" />
        <reg.1.server reg.1.server.1.address="sip.example.com" reg.1.server.1.expires="300" reg.1.server.2.expires="300" />
        <reg.1.serverFeatureControl reg.1.serverFeatureControl.dnd="0" />
     </reg>

代码找到 old_name 字符串并进入 if 语句，然后打开 complete_filename.new 进行写入，但它显然从未在行中找到旧名称并且只是输出文件原样（即它不会用 new_name 代替 old_name）。

从代码中可以看出，我也用re.sub进行了类似的实验。我错过了什么？

Answer 1

lines = provisioning_file.read()

我觉得这不对。 read() 不是 return 行列表，它 return 是一个字符串。所以稍后当你做 for line in lines: 时，你不是逐行迭代，而是一次迭代一个字符。

尝试split迭代对象之前调整对象。我还建议更改其名称，以便更好地描述其内容。

with open(complete_filename, 'r') as provisioning_file:
   text= provisioning_file.read()
   # if the old_name is in this file
   if old_name in text:
     file_found = 1
     with open(complete_filename + '.new', 'w') as new_provisioning_file:
       for line in text.split("\n"):
         line = line.replace(old_name, new_name)
         new_provisioning_file.write(line + "\n")

编辑：替代方法：

old_name = 'Some User'
new_name = 'New User'

with open(complete_filename, 'r') as provisioning_file:
   lines = provisioning_file.readlines()
   # if the old_name is in this file
   if any(old_name in line for line in lines):
     file_found = 1
     with open(complete_filename + '.new', 'w') as new_provisioning_file:
       for line in lines:
         line = line.replace(old_name, new_name)
         new_provisioning_file.write(line)

Python 搜索行中的字符串

Python search for string in line

python

string

replace

substitution