Python 2：字符串中的字符替换

Question

I need to convert a string into a new string: Each character in the new string must be '(' if that character appears only once in the original string, or ')' if that character appears more than once in the original string. Could you please help me?

myword = "attachment"

def duplicate_encode(word):
    from collections import Counter
    lst = list(word)
    counts = Counter(lst)
    newwrd = ""
        for key, value in counts.iteritems():
            if value > 1:
                newwrd += key.replace(key, ")")
            else: 
                newwrd += key.replace(key, "(")
        return newwrd

print duplicate_encode(myword)

My output: )((((()

Output expected ))))((((()

Edit: in case of upper cases, I do not want to consider them (IE "Fanfare" => "))())((" )

Answer 1

Just iterate Counter object and replace those characters where count equals 1 by ( and everything else by )

>>> from collections import Counter
>>> myword = "attachment"
>>> def duplicate_encode(word):
...     ct = Counter(word)
...     for k, v in ct.items():
...         if v == 1:
...             word = word.replace(k, '(')
...         else:
...             word = word.replace(k, ')')
...     return word
... 
>>> duplicate_encode(myword)
'))))((((()'

Answer 2

Using str.join to map all the characters in a string:

from collections import Counter
def duplicate_encode(word):
  counter = Counter(word)
  return "".join(")" if counter[c] > 1 else "(" for c in word)
print duplicate_encode("attachment") # "))))((((()"

Answer 3

Ok, solved, thanks to Tamas (added word.lower to his solution for the uppercase problem) and thank you all for your help!

def duplicate_encode(word):
    from collections import Counter
    nwrd = word.lower()
    counter = Counter(nwrd)
    return "".join(")" if counter[c] > 1 else "(" for c in nwrd)