Python - Suppression des doublons d'une chaîne

Question

def remove_duplicates(strng): 
    """ 
    Returns a string which is the same as the argument except only the 
    first occurrence of each letter is present. Upper and lower case 
    letters are treated as different. Only duplicate letters are removed, 
    other characters such as spaces or numbers are not changed. 

    >>> remove_duplicates('apple') 
    'aple' 
    >>> remove_duplicates('Mississippi') 
    'Misp' 
    >>> remove_duplicates('The quick brown fox jumps over the lazy dog') 
    'The quick brown fx jmps v t lazy dg' 
    >>> remove_duplicates('121 balloons 2 u') 
    '121 balons 2 u' 
    """ 
    s = strng.split() 
    return strng.replace(s[0],"") 

écriture d'une fonction pour se débarrasser des lettres en double mais jusqu'à présent ont joué pendant une heure et ne peuvent pas obtenir quoi que ce soit. L'aide serait appréciée, merci.

Answer 1

Pas le plus efficace, mais la façon la plus simple est:

>>> s = 'The quick brown fox jumps over the lazy dog' 
>>> import string 
>>> n = '' 
>>> for i in s: 
     if i not in string.ascii_letters: 
      n += i 
     elif i not in n: 
      n += i 


>>> n 
'The quick brown fx jmps v t lazy dg' 

Answer 2

try this ...

def remove_duplicates(s): 
    result = "" 
    dic = {} 
    for i in s: 
     if i not in dic: 
      result+=i 
      if ord(i.lower()) >= ord('a') and ord(i.lower()) <= ord('z'): 
       dic[i] = 1 
    return result 

Answer 3

En utilisant une compréhension de la liste:

>>> from string import whitespace, digits 
>>> s = 'The quick brown fox jumps over the lazy dog' 
>>> ''.join([c for i, c in enumerate(s) if c in whitespace+digits \ 
                 or not c in s[:i]])