各位大神，想请教一下，我想把下面的txt内容进行提取并且保存到另外一个txt文档中，应该如何操作，使用的是python3
--------------------------A-------------------------
1
2
3
4
5
--------------------------B-------------------------
使用以下的代码，可以提取到内容，但是结果是list，并且无法进行换行，请问还有其它好的方法吗，谢谢！
import re
date = []
recording = False
with open('data/2.txt','r') as filename:
    for line in filename:
        line = line.strip()
        
        if line == '--------------------------B--------------------------':
            break

        if recording:
            date.append(line)

        if line == '--------------------------A-------------------------':
            recording = True
            filename.write
             '\n'.join(date)

print(date)

import re
date = []
recording = False
with open('data/2.txt','r') as filename:
    lines=filename.readlines()
    with open('data/3.txt','w') as fileout:
        for line in lines:
            line = line.strip()
            
            if line == '--------------------------B--------------------------':
                break

            if recording:
                date.append(line)
                fileout.write(line+"\n")

            if line == '--------------------------A-------------------------':
                recording = True
print(date)

[此贴子已经被作者于2019-11-27 15:45编辑过]

非常谢谢，解决了我很久的问题，我是刚刚学习python。谢谢！

您好！我还能不能请教一下。在匹配'--------------------------B--------------------------'这个时我使用re.findall没有办法进行正则表达式的匹配，我尝试使用b来验证一下，还是没有办法来匹配到。请问我是那里有错吗？

import re
print('输入设备名称:',end='')
devicename = input()
devicenametemp = 'tempdata/' + devicename + '_CatalystAndAsr_version' + '.txt'
devicename = 'data/'+ devicename + '.txt'

date = []
recording = False
with open(devicename,'r') as filename:
     lines=filename.readlines()
     devicefile = filename.read()
     
   
     with open(devicenametemp,'w') as fileout:
        for line in lines:
            line = line.strip()
            b =re.findall('.*B.*',devicefile)
            if line == re.findall('.*B.*',line) :
                break

            if recording:
                date.append(line)
                fileout.write(line+"\n")

            if line == re.findall('.*A.*',line):
                recording = True
print(b)

lines=filename.readlines()
devicefile = filename.read()
readlines()会把所有内容存放到lines里,同时filename指针会指向文件最后,这时你再用filename.read()读取的只会是空.
你直接使用line就可以b =re.findall('.*B.*',line);为啥要用 devicefile .在循环里他是不变的空值.

非常高兴能看到您的回复，我使用您提供的代码运行是正常的，如果我把 if line == '--------------------------B--------------------------':使用re.findall来替换，发现是不行，经过刚刚的测试，我发现是不是通过re.findall来提取结果的是list，而if需要匹配的str，导致if无法生效。谢谢！
import re
date = []
recording = False
with open('data/2.txt','r') as filename:
    lines=filename.readlines()
    with open('data/3.txt','w') as fileout:
        for line in lines:
            line = line.strip()
            
            if line == '--------------------------B--------------------------':
                break

            if recording:
                date.append(line)
                fileout.write(line+"\n")

            if line == '--------------------------A-------------------------':
                recording = True
print(date)

替换如下
import re
date = []
recording = False
with open('data/2.txt','r') as filename:
    lines=filename.readlines()
    with open('data/3.txt','w') as fileout:
        for line in lines:
            line = line.strip()
            
            if line ==  re.findall('.*B.*',line) :
                break

            if recording:
                date.append(line)
                fileout.write(line+"\n")

            if line == re.findall('.*A.*',line):
                recording = True
print(date)

又麻烦您了，我刚刚测试了一下，我把list转为str就可以，但是遇到一个问题的是当4和5中间有个空的换行时，只能列出4的数据。无法列出5，可能是我的表达式有问题，我需要再研究一下，谢谢！
-------------------------A-------------------------
1
2
3
4

5
--------------------------B-------------------------



date = []
recording = False
with open(devicename,'r') as filename:
     lines=filename.readlines()
     
     with open(devicenametemp,'w') as fileout:
        for line in lines:
            line = line.strip()
            
           
            if line == (''.join(re.findall('.*B.*',line))):
                print(line)
                break

            if recording:
                date.append(line)
                fileout.write(line+"\n")

            if line == (''.join(re.findall('.*A.*',line))):
               
                recording = True

看来这个论坛热心人也不少，以前怎么没听说呢