python Generate an alphanumeric Sequence

Question

I need a custom alphanumeric sequence for a custom_id on django model for each Product.

def save(self, *args, **kwargs):
    if self.custom_id is None:
        self.custom_id = f"{custom_seq(self.id)}"
    return super(Product, self).save(*args, **kwargs)

I want custom Alphanumeric sequence to be generated as:

eg. letters=4, digits=3 then,
'AAAA001', 'AAAA002', 'AAAA003'... 'ZZZZ999'
if letters =3 and digits =4
'AAA0001', 'AAA0002'... 'ZZZ9999'

Here is my try:

def custom_seq(pk, letter=4, digits=3):
  init = ''
  alpha = string.ascii_uppercase
  for i in alpha:
    for j in alpha:
      for k in alpha:
         for l in alpha: 
            yield(i+j+k+l)

This will genrate only 'AAAA' to 'ZZZZ', but not sure how to add digits in front of it and make this dynamic.

What do you mean by "make this dynamic"? And the `itertools` has a function, `product`, which might be of help. — Scott Hunter, Aug 31 '20 at 02:43
@ScottHunter - Thanks, let me check `product`, Dynamic means- in my code you might have observed I have written 4 for looks when letters are 4. Those 4 loops should dynamic, so that if I change the `letters` to some other `number` say 3 or 5 for loops should change for that number of times. — trex, Aug 31 '20 at 02:46
what do you want the `self.id` to do when you passed it to `custom_seq` ? Seems like you want a custom generator to yield `AAA001` ... , but how do you want to control where does the sequence start from? Like do you want to control whether first sequence is `AAA001` or `AAA999`? — fusion, Aug 31 '20 at 02:48
@fusion - please ignore, I was planning to initialize with id `itself` instead of digits but the problem was it could have any number of digits such as 2 digits 3 digits etc. which would vary my sequence length — trex, Aug 31 '20 at 02:50
Are you perhaps looking for something like this? https://stackoverflow.com/a/2030081/1294308 — rriehle, Aug 31 '20 at 02:52

score 3 · Accepted Answer · answered Aug 31 '20 at 02:50

You can use itertools.product in order to get the combinations of alphabets and digits easily.

import string
import itertools

def custom_seq(pk, letter=4, digits=3):
    alpha = string.ascii_uppercase
    digit = string.digits
    alpha_list = [alpha]*letter
    digit_list = [digit]*digits
    for i in itertools.product(*alpha_list):
        for j in itertools.product(*digit_list):
            yield "".join(i + j)
            # print("".join(i + j))

python Generate an alphanumeric Sequence

1 Answers1