how can I add different character to blank spaces in a string?(or replace specific word in a string with different characters or numbers.)

Question

how can I add characters/numbers to blank spaces like this:

Today the ---- is cloudy, but there is no ----.

Today the --a)-- is cloudy, but there is no --b)--.(desired result)

As you can see blank spaces are not replaced with a fixed character, which makes using python replace() method complicated for me.

Answer 1

You can use re.sub(). It allows you to use a function as the replacement, so the function can increment the character each time it's called. I've written the function as a generator.

import re

def next_char():
    char = 'a'
    while True:
        yield char
        char = chr(ord(char) + 1)
        if char > 'z':
            char = 'a'

seq = next_char()

str = 'Today the ---- is cloudy, but there is no ----.'
str = re.sub(r'----', lambda x: ('--' + next(seq) + ')--'), str)

print(str)

DEMO