切片或数组中的动态范围

Question

我有从 netaddr 生成 IP 子网信息的 python 脚本。

from netaddr import *
ipnetwork = raw_input("Enter IP address: ")
ip = IPNetwork(ipnetwork)
print "Network ID:", ip.network
print "Network Broadcast:", ip.broadcast
print "Subnet Mask:", ip.netmask
print "Prefix Length:", ip.prefixlen
print "Wildcard Mask:", ip.hostmask
print "Network Size:", ip.size

print "Host range is:", ip[1], "-", ip[-2]
for ip in IPNetwork(ipnetwork).iter_hosts():
    print '%s' % ip

这行得通。我遇到麻烦的地方是我想“保留”第一个和最后三个地址。这是我当前输出的示例：

Enter IP address: 192.168.100.17/28
Network ID: 192.168.100.16
Network Broadcast: 192.168.100.31
Subnet Mask: 255.255.255.240
Prefix Length: 28
Wildcard Mask: 0.0.0.15
Network Size: 16
Host range is: 192.168.100.17 - 192.168.100.30
192.168.100.17
192.168.100.18
192.168.100.19
192.168.100.20
192.168.100.21
192.168.100.22
192.168.100.23
192.168.100.24
192.168.100.25
192.168.100.26
192.168.100.27
192.168.100.28
192.168.100.29
192.168.100.30

我想要的结果是

192.168.100.17 Reserved
192.168.100.18 Reserved
192.168.100.19 Reserved
192.168.100.20
192.168.100.21
192.168.100.22
192.168.100.23
192.168.100.24
192.168.100.25
192.168.100.26
192.168.100.27
192.168.100.28 SW2-VLAN 100
192.168.100.29 SW1-VLAN 100
192.168.100.30 HSRP VLAN 100

我认为切片会起作用并且确实有效，直到我选择不同的子网长度。我不知道如何动态地将地址四（第一个非保留）切片到最后一个地址减去三。我找不到任何解决方案（切片、数组、索引），它会根据子网大小减去第一个和最后三个地址是动态的。任何指针将不胜感激。

Answer 1

我对这个问题有点困惑。如果您想管理IPNetwork(ipnetwork).iter_hosts()，您可能只想简单地列出并理解它们。

def handle(i, data):
    # Each ip, or 'data', can be returned as a
    # new value to fill that list or we could return
    # The objects themselves.
    if i < 3:
        return str(data) + " Reverse"
    elif i > (total - 3):
        return str(data)
    else:
        return str(data) + " SW1-VLAN 100"

ips_to_manage = [handle(i, addr) for i, addr in \
                 enumerate(IPNetwork(ipnetwork).iter_hosts())]
for ip in ips_to_manage:
    print '%s' % ip

您必须自己找出总数。 len(IPNetwork(ipnetwork).iter_hosts()) 应该做的伎俩。 这样，您就可以随心所欲地处理它们了。

这只是打印它们，但是，如果您想做其他事情，例如作为对象本身的回报，那么欢迎您。