How do I print the first and last value?

Question

The below part code prints all the host IP Address that lies in the Subnet, I want to modify the code so that it prints only the starting address and the last address of this list

How do I use an array here to print the first and last value?

import ipaddress
print('enter subnet')  # in CIDR Format
x = input()
IP= ipaddress.ip_network(x, strict = False)
for y in IP.hosts():
 print(y)

Current Output

enter subnet
192.0.0.0/29
192.0.0.1
192.0.0.2
192.0.0.3
192.0.0.4
192.0.0.5
192.0.0.6

Desired output

HostMin:   192.0.0.1  
HostMax:   192.0.0.6

=========================================

UPDATE:

After using the list i was able to print the first and last values

however this takes quite longer to compute whenever i give a large
subnet

like 192.0.0.0/8 takes longer to print the first and last value, 

for: IPV6 address calculations it hangs forever, 
for: example: the  IPV6 address is 2001:db8::1/96 

this list will have 4294967294 elements since this IPV6 subnet has
these many IP address and it hangs forever to print the first and
last element of the list

Possible duplicate of http://stackoverflow.com/questions/930397/getting-the-last-element-of-a-list-in-python — Abhimanyu singh, Apr 07 '17 at 07:08

Himaprasoon · Accepted Answer · 2017-04-07T20:32:40.817

2

list[0] and list[-1] gets you the first and last element respectively

import ipaddress
print('enter subnet')  # in CIDR Format
x = input()
IP= ipaddress.ip_network(x, strict = False)
k = list(IP.hosts())
print("HostMin: ",k[0])
print("HostMax: ",k[-1])

Updated Answer for getting first and last IP without generating the whole IP range

import ipaddress
def hosts(IPTYPE):
    """Custom function derived from IPv6Network/IPv4Network.hosts to get only first and last host

    """
    network = int(IPTYPE.network_address)
    broadcast = int(IPTYPE.broadcast_address)
    return IPTYPE._address_class(network+1),IPTYPE._address_class(broadcast)

print('enter subnet')  # in CIDR Format
x = input()
IP= ipaddress.ip_network(x, strict = False)
m = hosts(IP)
print("HostMin: ",m[0])
print("HostMax: ",m[1])

edited Apr 07 '17 at 20:32

answered Apr 07 '17 at 07:00

Himaprasoon

2,609
3
25
46

however this takes quite longer to compute whenever i give a large subnet, like 192.0.0.0/8 takes longer to print the first and last value, and for IPV6 address calculations it hangs forever, for example if i enter the IPV6 address as 2001:db8::1/96 it has 4294967294 elements and it hangs to print the first and last element of the list – Rahul Apr 07 '17 at 19:17
I have updated my answer to include a custom method derived from ipaddress module which gives only the first and last IP instantaneously. – Himaprasoon Apr 07 '17 at 20:34

Axel · Answer 2 · 2017-04-07T07:10:29.427

0

replace for y in IP.hosts(): by y = list(IP.hosts()) and then you can do

print y[0]
print y[-1]

You should read the doc of hosts() function "Returns an iterator over the usable hosts in the network"

edited Apr 07 '17 at 07:10

answered Apr 07 '17 at 07:00

Axel

41
1
5

this takes quite longer to compute whenever i give a large subnet, like 192.0.0.0/8 takes longer to print the first and last value, and for IPV6 address calculations it hangs forever, for example if i enter the IPV6 address as 2001:db8::1/96 it has 4294967294 elements and it hangs to print the first and last element of the list – Rahul Apr 07 '17 at 19:22

score 0 · Answer 3 · answered Apr 07 '17 at 07:15

0

You don't use an array here. Use a list!

first_item = list[0]
last_item = list[-1]

answered Apr 07 '17 at 07:15

kame

20,848
33
104
159

How do I print the first and last value?

UPDATE:

3 Answers3