How to replace pattern of stars with message?-CodePudding

I am trying to format a message by repeating its items according to a pattern:

message = '123'
pattern = '** *** **** * **'

Expected output : 12 312 3123 1 23

Below is my current code, but is outputs: 123 12 31 231 23

def main():

    message = "123"
    
    pattern = "** *** ** ** *"
    print(patterned_message(message, pattern))

def patterned_message(message, pattern):
    
    c = 0
    res = ""
    jstr = [x.strip(" ") for x in message]
    for i in pattern:
        if c == (len(jstr)):
            c = 0
        else:
            if i == " ":
                res  = " "
            else:
                res  = i.replace("*","{}".format(jstr[c]))
                c  = 1
          
    return res        

   

if __name__ == '__main__':
    main()

CodePudding user response：

You can use itertools.cycle as a generator and a small list comprehension:

from itertools import cycle

message = '123'
pattern = '** *** **** * **'

x = cycle(message)

out = ''.join(next(x) if i == '*' else ' ' for i in pattern)

print(out)

output: '12 312 3123 1 23'

Just for python learners, here is a more classical approach:

def patterned_message(message, pattern):
    out = [' ']*len(pattern)
    n = 0
    for i, char in enumerate(pattern):
        if char == '*':
            out[i] = message[n%len(message)]
            n =1
    return ''.join(out)

patterned_message('123', '** *** **** * **')