How remove duplicate letters in a string

Question

Is there a way to remove duplicate characters? For example if we input "hello", the output will be "helo"; another example is "overflow", the output would be "overflw"; another example "paragraphs", the output would be "parghs".

I have tried

def removeDupes(mystring):
    newStr = ""
    for ch in string:
        if ch not in newStr:
            newStr = newStr + ch
    return newStr

So what is the problem with that code? — By the way, the argument is called `mystring`, but you use `string` in the `for` loop. — Robin Krahl, Oct 28 '13 at 01:32

score 1 · Accepted Answer · answered Oct 28 '13 at 01:32

Change string to mystring:

def removeDupes(mystring):
    newStr = ""
    for ch in mystring:
        if ch not in newStr:
            newStr = newStr + ch
    return newStr

print removeDupes("hello")
print removeDupes("overflow")
print removeDupes("paragraphs")

>>> 
helo
overflw
parghs

score 1 · Answer 2 · answered Oct 28 '13 at 01:34

1

yes with something called a set:

unique = set()

[ unique.add(c) for c in 'stringstring' ]

answered Oct 28 '13 at 01:34

ennuikiller

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3

This wouldn't preserve order, if that's important to the OP – Ben Oct 28 '13 at 01:34
also, wouldn't just `set(x for x in 'stringstring')` be better and more Pythonic? – tckmn Oct 28 '13 at 01:38

score 1 · Answer 3 · answered Oct 28 '13 at 01:34

1

I would use collections.OrderedDict for this:

>>> from collections import OrderedDict
>>> data = "paragraphs"
>>> print "".join(OrderedDict.fromkeys(data))
parghs

answered Oct 28 '13 at 01:34

Ben

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-1 for plagiarizing [this answer](http://stackoverflow.com/a/9841328/1223693) – tckmn Oct 28 '13 at 01:35
1

@Doorkob I wasn't aware of that answer - it's just the way I would do it. – Ben Oct 28 '13 at 01:36
okay, I'll just assume good faith here and believe you. anyway, it's a duplicate question – tckmn Oct 28 '13 at 01:36
You're right, it is. Flagged it! – Ben Oct 28 '13 at 01:40

How remove duplicate letters in a string

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