Startswith with a range of number instead an unit

Question

ip = a list of ips
ipf = list(filter(lambda x: x if not x.startswith(str(range(257,311))) else None, ip))

Is is possible to do something like this? I tested it and it doesn't work. I'd like to delete all ips from "ip" list that start with 256. 257. 258. ecc... to 310.

The parts of a valid IP will be in the range 0 to 255 (both inclusive). — thefourtheye, Oct 01 '16 at 14:45

Martijn Pieters · Accepted Answer · 2016-10-01T15:46:45.780

3

No, str.startswith() doesn't take a range.

You'd have to parse out the first part and test it as an integer; filtering is also easier done with a list comprehension:

[ip for ip in ip_addresses if 257 <= int(ip.partition('.')[0]) <= 310]

The alternative would be to use the ipaddress library; it'll reject any invalid address with a ipaddress.AddressValueError exception, and since addresses that start with anything over 255 are invalid, you can easily co-opt that to filter out your invalid addresses:

import ipaddress

def valid_ip(ip):
    try:
        ipaddress.IPv4Address(ip)
    except ipaddress.AddressValueError:
        return False
    else:
        return True

[ip for ip in ip_addresses if valid_ip(ip)]

edited Oct 01 '16 at 15:46

answered Oct 01 '16 at 14:46

Martijn Pieters

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so in my case I need to use: ipf = [x for x in ip if 257 <= int(x.partition('.')[0]) <= 310] right? – CatchJoul Oct 01 '16 at 14:52
@Thavivelball: yes; I renamed `ip` to `ip_addresses` to use clearer variable names. – Martijn Pieters Oct 01 '16 at 14:58
1

@Thavivelball: since you didn't provide any sample input dat or the expected output, I can't help you more than this. – Martijn Pieters Oct 01 '16 at 15:08
It works actually.... just you mistyped lol... you typed "ipaddress.IPV4Address(ip)" instead of "ipaddress.IPv4.Address(ip)". Thanks – CatchJoul Oct 01 '16 at 15:45
Corrected; it was typed from memory. – Martijn Pieters Oct 01 '16 at 15:46
@Thavivelball: that's not an [mcve]. Please isolate the wrong results that you expected not to be added to the blacklist. – Martijn Pieters Oct 01 '16 at 21:21

Startswith with a range of number instead an unit

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