文件练习

#!/usr/bin/env python

# 读取
def fetch(backend):
    result = []
    with open(‘account.txt‘,‘r‘)as f:
        flag =False
        for line in f:
            if line.strip().startswith("backend") and line.strip() == "backend " + backend:
                flag = True
                continue
            if line.strip().startswith("backend"):
                flag = False
                break
            if flag and line.strip():
                result.append(line.strip())
    return result

user = input("请选择:")
ret = fetch(user)
print(ret)

#写入
def add(backend,record):
    record_list = fetch(backend)
    if not record_list: #backend不存在
        with open(‘b.txt‘,‘r‘)as old, open(‘new.conf‘,‘w‘)as new:
            for line in old:
                new.write(line)
            new.write(‘backend ‘ + backend + ‘\n‘)
            new.write(‘ ‘ * 8 + record + ‘\n‘)

    else:
        # backend已存在
        if record in record_list:
            import shutil
            shutil.copy(‘b.txt‘,‘new.conf‘)
            pass
        else:
            #backed存在 record不存在
            record_list.append(record)
            with open(‘b.txt‘,‘r‘)as old,open(‘new.conf‘,‘w‘)as new:
                flag = False
                for line in old:
                    if line.strip().startswith(‘backend‘) and line.strip() == ‘backend ‘ + backend:
                        flag = True
                        new.write(line)  #写标题
                        for new_line in record_list:
                            new.write(‘ ‘ * 8 + new_line + ‘\n‘)
                    if flag and line.strip().startswith(‘backend‘):
                        flag = False
                        new.write(line)
                        continue #防止重复写标题
                    if line.strip() and not flag:   #后面不是标题的
                        new.write(line)