In [8]:

    

def uniqueChars(string):
    temp = set()
    for i in string:
        if i in temp:
            return False
        temp.add(i)
    return True

def uniqueChars2(string):
    temp = set()
    for i in string:
        if string.count(i) > 1:
            return False
    return True

def uniqueChars3(string):
    return len(set(string)) == len(string)


    

In [11]:

    

print(uniqueChars("fro"))


    

    




True

In [12]:

    

from nose.tools import assert_equal
assert_equal(uniqueChars3(''), True)
assert_equal(uniqueChars3('foo'), False)
assert_equal(uniqueChars3('bar'), True)