remove from a list of tuples according to the second part of the tuples in python

Question

contacts.remove((name,ip)) i have the ip and its unique, i want to remove this tuple from contacts according to the ip and no need to name, i just tried this "contacts.remove((pass,ip))", but i encountered an error.

Answer 1

contacts = [(name, ip) for name, ip in contacts if ip != removable_ip]

or

for x in xrange(len(contacts) - 1, -1, -1):
    if contacts[x][1] == removable_ip:
        del contacts[x]
        break # removable_ip is allegedly unique

The first method rebinds contacts to a newly-created list that excludes the desired entry. The second method updates the original list; it goes backwards to avoid being tripped up by the del statement moving the rug under its feet.

Answer 2

This goes thought the contacts and removes any list which second item is the wanted ip:

for c in contacts:
    if c[1] == wanted_ip:
        contacts.remove(c)

A second safer option is this:

contacts = original_contacts[:]
for c in contacts:
    if hasattr(c, '__iter__'):
        if len(c) == 2:
            if c[1] == wanted_ip:
                contacts.remove(c)

Answer 3

Since the ip to remove is unique, you don't need all the usual precautions about modifying a contained you're iterating on -- thus, the simplest approach becomes:

for i, (name, anip) in enumerate(contacts):
  if anip == ip:
    del contacts[i]
    break