How to put a colon (:) after every second character?

Question

I want to put : after every second character:

def maccim():
    l = ["A", "B", "C", "D", "E", "F", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"]
    macim = random.sample(l, 12)
    szo = ""
    for x in macim:
        szo += x
    print(szo)

maccim()

I want to get like this: 94:EA:60:F8:BC:2D as a mac address.

bluevulture · Accepted Answer · 2021-12-21T12:59:06.583

1

The simplest way would be to use enumerate when you put together the string:

import random

def maccim():
    list=["A","B","C","D","E","F","0","1","2","3","4","5","6","7","8","9"]
    macim=random.sample(list,12)
    szo=""
    for index, x in enumerate(macim):
        szo+=x
        if (index+1)%2 == 0:
            szo+=":"
    szo = szo[:-1]
    print(szo)
maccim()

Then you can use the index to determine if you need to add an ':'

edited Dec 21 '21 at 12:59

answered Dec 21 '21 at 12:35

bluevulture

422
4
16

that would be good, but I don't know how to remove the : at the end of it 75:1A:C2:9E:DB:36: – blnt09 Dec 21 '21 at 12:48
1

This will add an addtional `:` after the last character – Sash Sinha Dec 21 '21 at 12:48
1

Yes, you're right. You can use `szo =szo[:-1]` after the loop to remove the last element from the string. – bluevulture Dec 21 '21 at 12:58

score 1 · Answer 2 · answered Dec 21 '21 at 12:49

Create couples of characters with slicing and then just join them with a ::

import random

def maccim():
    l = ["A","B","C","D","E","F","0","1","2","3","4","5","6","7","8","9"]
    macim = ''.join(random.sample(l, 12))

    print(':'.join(macim[i:i+2] for i in range(0, len(macim), 2)))
    
maccim()

score 0 · Answer 3 · answered Dec 21 '21 at 12:33

You can do it with brutal way

for i in range(len(macim)):
    szo += macin[i]
    if i % 2 and i < len(macim) - 1:
        szo += ":"

or fancy way

def chunks(l, n):
    n = max(1, n)
    return (l[i:i+n] for i in range(0, len(l), n))

...

":".join(chunks(macin, 2))

score 0 · Answer 4 · answered Dec 21 '21 at 12:35

Here is another solution using list splice,

import random


def maccim():
    list_ = [
        "A", "B", "C", "D", "E", "F", "0", "1", "2", "3", "4", "5", "6", "7", "8", "9"
    ]
    macim = random.sample(list_, 12)

    return ":".join([i + j for i, j in zip(macim[::2], macim[1::2])])


print(maccim())

score 0 · Answer 5 · answered Dec 21 '21 at 12:50

0

Just for fun, if you wanted a simple one-liner using zip and map:

import string
import random

chars = random.sample(string.hexdigits[:16], 12)

':'.join(map(''.join, zip(chars[::2], chars[1::2])))

This will output:

'07:9d:b5:1c:84:ae'

answered Dec 21 '21 at 12:50

S3DEV

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How to put a colon (:) after every second character?

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