Inserting a character at regular intervals in a list

Question

I am trying to convert 10000000C9ABCDEF to 10:00:00:00:c9:ab:cd:ef

This is needed because 10000000C9ABCDEF format is how I see HBAs or host bust adapaters when I login to my storage arrays. But the SAN Switches understand 10:00:00:00:c9:ab:cd:ef notation.

I have only been able to accomplish till the following:

#script to convert WWNs to lowercase and add the :.
def wwn_convert():
    while True:
        wwn = (input('Enter the WWN or q to quit- '))
        list_wwn = list(wwn)
        list_wwn = [x.lower() for x in list_wwn]
        lower_wwn = ''.join(list_wwn)
        print(lower_wwn)
    if wwn == 'q':
        break

wwn_convert()

I tried ':'.join, but that inserts : after each character, so I get 1:0:0:0:0:0:0:0:c:9:a:b:c:d:e:f

I want the .join to go through a loop where I can say something like for i in range (0, 15, 2) so that it inserts the : after two characters, but not quite sure how to go about it. (Good that Python offers me to loop in steps of 2 or any number that I want.)

Additionally, I will be thankful if someone could direct me to pointers where I could script this better...

Please help.

I am using Python Version 3.2.2 on Windows 7 (64 Bit)

Answer 1

Here is another option:

>>> s = '10000000c9abcdef'
>>> ':'.join(a + b for a, b in zip(*[iter(s)]*2))
'10:00:00:00:c9:ab:cd:ef'

Or even more concise:

>>> import re
>>> ':'.join(re.findall('..', s))
'10:00:00:00:c9:ab:cd:ef'