python - 如何在Python中使用正则表达式分割/etc/network/interfaces

Question

我正在尝试将 Ubuntu 上的 /etc/network/interfaces 文件格式分解为各个节(正如手册页所称的那样)。

这是我测试脚本的示例接口(interface)文件:

# The loopback network interface
auto lo
iface lo inet loopback

auto eth0
iface eth0 inet static
    address 192.168.2.7
    netmask 255.255.255.0
    network 192.168.2.0
    broadcast 192.168.2.255
    gateway 192.0.2.254
    dns-nameservers 12.34.56.78 12.34.56.79

auto eth0:0
allow-hotplug eth0:0
iface eth0:0 inet static
    address 192.168.1.43
    netmask 255.255.255.0

auto eth1
iface eth1 inet dhcp

auto eth2
iface eth2 inet6 static
    address 2001:db8::c0ca:1eaf
    netmask 64
    gateway 2001:db8::1ead:ed:beef

auto br0
iface br0 inet static
    address 10.10.0.15
    netmask 255.255.255.0
    gateway 10.10.0.1
    bridge_ports eth0 eth1
    up /usr/sbin/brctl stp br0 on

我需要的是保存每个节的字符串数组(iface、mapping、auto、allow-\w+、source(-\w+)? 和注释)及其后面的所有文本，直到下一节开始。

我已经尝试过这样的代码，听起来应该可以工作，但它捕获了一个字符串中的所有节:

re.split(r'^(iface|mapping|auto|allow-\w+|source(-\w)?|#.*)[.\n]+?',
    open('/etc/network/interfaces').read(), flags=re.MULTILINE)

如何更正正则表达式来实现此目的？

Python版本是2.7

Answer 1

您不需要正则表达式:

def stanza(fle):
    with open(fle) as f:
        vals = ("iface", "mapping", "auto", "allow-", "source")
        tmp = []
        for line in f:
            if line.startswith(vals):
                yield tmp
                tmp = [line]
            else:
                tmp.append(line)
    if tmp:
        yield tmp


from pprint import pprint as pp
pp(list(stanza("foo.txt")))

输出:

[['# The loopback network interface\n'],
 ['auto lo\n'],
 ['iface lo inet loopback\n', '\n'],
 ['auto eth0\n'],
 ['iface eth0 inet static\n',
  '    address 192.168.2.7\n',
  '    netmask 255.255.255.0\n',
  '    network 192.168.2.0\n',
  '    broadcast 192.168.2.255\n',
  '    gateway 192.0.2.254\n',
  '    dns-nameservers 12.34.56.78 12.34.56.79\n',
  '\n'],
 ['auto eth0:0\n'],
 ['allow-hotplug eth0:0\n'],
 ['iface eth0:0 inet static\n',
  '    address 192.168.1.43\n',
  '    netmask 255.255.255.0\n',
  '\n'],
 ['auto eth1\n'],
 ['iface eth1 inet dhcp\n', '\n'],
 ['auto eth2\n'],
 ['iface eth2 inet6 static\n',
  '    address 2001:db8::c0ca:1eaf\n',
  '    netmask 64\n',
  '    gateway 2001:db8::1ead:ed:beef\n',
  '\n'],
 ['auto br0\n'],
 ['iface br0 inet static\n',
  '    address 10.10.0.15\n',
  '    netmask 255.255.255.0\n',
  '    gateway 10.10.0.1\n',
  '    bridge_ports eth0 eth1\n',
  '    up /usr/sbin/brctl stp br0 on']]

如果您想删除空格，请使用 line.strip() 将其删除。