The task is to generate all the possible permutations of a given string. A permutation of a string is a rearrangement of its characters. For example, the permutations of "ABC" are "ABC", "ACB", "BAC", "BCA", "CAB", and "CBA". The number of permutations of a string with n unique characters is n! (factorial of n).

Using itertools.permutations

itertools module in Python provides a simple function called permutations that can generate all possible permutations of a string. This method is the easiest and most efficient, especially when working with built-in Python libraries.

import itertools

s = "GFG"
li = [''.join(p) for p in itertools.permutations(s)]
print(li)

Explanation:

• itertools.permutations(s): generates all possible permutations of the string s, returning each permutation as a tuple.
• ''.join(p): converts each tuple p into a string by concatenating its elements.
• list comprehension collects all the joined strings (permutations) into a list.

Using Recursion

Recursion repeatedly breaks the problem into smaller parts. In string permutation, it means choosing one character and recursively arranging the remaining characters, generating all possible orderings systematically.

def permute(s, s2):
    if len(s) == 0:
        print(s2, end=' ')
        return
    
    for i in range(len(s)):
        char = s[i]
        left_s = s[0:i]
        right_s = s[i+1:]
        rest = left_s + right_s
        permute(rest, s2 + char)

s1 = "GFG"
s2 = ""
permute(s1, s2)

GFG GGF FGG FGG GGF GFG 

Explanation:

• If the string s is empty, print the accumulated answer.
• For each character in s, remove the character and recursively permute the remaining characters while adding the character to answer.
• Call permute(s, answer) with the initial string and an empty answer to start generating permutations.

Related Articles:

• Generate all permutation of a set in Python
• Print all Unique permutations of a given string.