What are string permutations and how can I generate them?

What are string permutations and how can I generate them?

String permutations are all possible arrangements of the characters in a string. For example, the permutations of 'abc' are 'abc', 'acb', 'bac', 'bca', 'cab', and 'cba'. You can generate them using recursive algorithms or libraries in programming languages.

Can you show me a simple code example to generate permutations?

Sure! Here's a simple Python example using recursion:

def permute(s):
    if len(s) == 1:
        return [s]
    permutations = []
    for i, char in enumerate(s):
        for perm in permute(s[:i] + s[i+1:]):
            permutations.append(char + perm)
    return permutations

print(permute('abc'))

What if I want to generate permutations of a string with repeated characters?

In that case, you can use a set to avoid duplicates. Here's an updated version of the code:

def permute_unique(s):
    if len(s) == 1:
        return [s]
    permutations = set()
    for i, char in enumerate(s):
        for perm in permute_unique(s[:i] + s[i+1:]):
            permutations.add(char + perm)
    return list(permutations)

print(permute_unique('aabc'))