Python在行中搜索字符串

Question

我有以下代码，我认为应该可以，但是似乎不行：

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文件的选择，下面是其中之一的示例代码片段：

  <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>

该代码找到old_name字符串并进入if语句，然后打开complete_filename.new进行写入，但是显然它从未在各行中找到该旧名称，而是按原样输出文件（即，它不会用new_name代替old_name ） 。

从代码中可以看出，我还对re.sub进行了实验，结果相似。 我想念什么？

Answer 1

lines = provisioning_file.read()

这在我看来不对。 read()不返回行列表，而是返回单个字符串。 因此，稍后for line in lines: ，不是逐行迭代，而是一次迭代一个字符。

遍历之前，请尝试split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)