Python在写入文件时保留缩进

Question

我有一段Python代码，它可以把括号里相同的词汇归在一起，并把剩下的文本合并起来。但是问题是，它在写入时没有保留原来的缩进。

我的代码：

import re
import collections
class Group:
    def __init__(self):
        self.members = []
        self.text = []

with open('text.txt','r+') as f:
    groups = collections.defaultdict(Group)
    group_pattern = re.compile(r'^(\S+)\((.*)\)$')
    current_group = None
    for line in f:
        line = line.strip()
        m = group_pattern.match(line)
        if m:    # this is a group definition line
            group_name, group_members = m.groups()
            groups[group_name].members += filter(lambda x: x not in groups[group_name].members , group_members.split(','))
            current_group = group_name
        else:
            if (current_group is not None) and (len(line) > 0):
                groups[current_group].text.append(line)
    f.seek(0)
    f.truncate()

    for group_name, group in groups.items():
        f.write("%s(%s)" % (group_name, ','.join(group.members)))
        f.write( '\n'.join(group.text) + '\n')

文本文件：text.txt

  Car(skoda,audi,benz,bmw)
    The above mentioned cars are sedan type and gives long rides efficient
 ......

  Car(Rangerover,audi,Hummer)
SUV cars are used for family time and spacious.

期望的输出：

  Car(skoda,audi,benz,bmw,Rangerover,Hummer)
    The above mentioned cars are sedan type and gives long rides efficient
 ......
SUV cars are used for family time and spacious.

但实际得到的是：

Car(skoda,audi,benz,bmw,Rangerover,Hummer)The above mentioned cars are sedan type and gives long rides efficient
 ......
SUV cars are used for family time and spacious.

Answer 1

你的问题出在你写这些行之前的格式处理上。

import re
import collections
class Group:
    def __init__(self):
        self.members = []
        self.text = []

with open('text.txt','r+') as f:
    groups = collections.defaultdict(Group)
    group_pattern = re.compile(r'^(\S+)\((.*)\)$')
    current_group = None
    for line in f:
        m = group_pattern.match(line)
        if m:    # this is a group definition line
            group_name, group_members = m.groups()
            groups[group_name].members += filter(lambda x: x not in groups[group_name].members , group_members.split(','))
            current_group = group_name
        else:
            if (current_group is not None) and (len(line) > 0):
                groups[current_group].text.append(line)

    with open("text.txt","w") as f:
        for group_name, group in groups.items():
            f.write("%s(%s)" % (group_name, ','.join(group.members)))
            f.write("\n")
            f.write( ''.join(group.text))
            f.write("\n")

Answer 2

你正在用这一行代码去掉字符串开头和结尾的空白字符：

line = line.strip()