[프로그래머스] 신규 아이디 추천

문제링크

.lower(), isalnum() 함수 사용하기!

파이썬

def solution(new_id):
    new_id = new_id.lower()
    answer = ''
    
    for i in new_id:
        if i.isalnum() or i in '-_.':
            answer += i
            
    while '..' in answer:
        answer = answer.replace('..','.')
    
    if answer[0] == '.' and len(answer) > 1:
        answer = answer[1:]
        
    if answer[-1] == '.':
        answer = answer[:-1]

    if answer == '':
        answer = 'a'

    if len(answer) > 15:
        answer = answer[:15]
        if answer[-1] == '.':
            answer = answer[:-1]
            
    if len(answer) < 3:
        answer = answer + answer[-1] * (3-len(answer))
    
    return answer