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Python

Posted by Derek Derek
Derek Derek
8,744 Points

[Python] permutation with duplicates

I am implementing a algorithm that prints out all permutations of a string with duplicates allowed. For example, "Hello" will have 5! number of outcomes. However, I am getting errors for my functions that I don't understand how to debug. Please help me.

def freq(s):
    my_dict = {}
    for l in s:
        if l not in my_dict:
            my_dict[l] = 0
        my_dict[l] += 1
    return my_dict

def printPerms1(letter_count_list, prefix, remaining, result):

    if len(remaining) == 0:
        result += prefix
        return result
    else:
        for l in letter_count_list:
            count = letter_count_list[l]
            if count > 0:
                result += l

                printPerms1(letter_count_list, prefix + l, remaining - 1, result)
    return result

def printPerms(s):
    letter_count_list = freq(s)
    prefix = s[0]
    remaining = len(s) - 1
    result = ""
    printPerms1(letter_count_list, prefix, remaining, result)


printPerms("Hello")
Nate Sturgeon
Nate Sturgeon
2,255 Points

The only error I found is in your line

if len(remaining) == 0:

Since remaining is an int, it has no length. However, the following may achieve your desired effect:

if remaining == 0:

However, I tried this, and discovered printPerms("Hello") returns None, which is obviously not your intended result. So there is more work to be done here.