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Find All Permutations of String in Python (Programs and Examples)

String permutations involve rearranging the characters of a string to create all possible combinations without repetition. The program for string permutation in Python can output a vast array of results, allowing you to explore different sequences, generate unique identifiers, or tackle challenging combinatorial problems. 

In this tutorial, we will learn how to find string permutations in Python, with different types of programs and insightful examples for better understanding.

Use Cases of Python String Permutation Programs:

  • Algorithm Design and Problem Solving: String permutations play a crucial role in algorithmic problem-solving, particularly in scenarios that involve searching, pattern matching, or generating all possible outcomes. By computing all permutations of a string, you can efficiently explore solution spaces and devise optimal algorithms.

  • Cryptography and Data Security: String permutations find applications in cryptography and data security domains. Permutations can be utilized in encryption techniques, key generation, or obfuscation methods, enhancing the security and integrity of sensitive information.

  • Combinatorial Analysis and Data Exploration: String permutations are valuable for combinatorial analysis, such as exploring different combinations of elements in a dataset. By generating all permutations of a string, you can evaluate various scenarios, analyze patterns, or enumerate possibilities in fields like data science, bioinformatics, or game theory.

To practice and master the concepts discussed below, we recommend using the online Python compiler by Tutorials Freak. It offers a seamless experience, allowing you to write, run, and experiment with Python Programs directly in your web browser. 

Find All Permutations of String in Python

To print all permutations of a string in Python, you can use the itertools module, which provides a function called permutations().

Code

from itertools import permutations

def find_permutations(string):
    perm_list = list(permutations(string))
    perm_strings = [''.join(perm) for perm in perm_list]
    return perm_strings

# Example usage
input_string = "abc"
permutations_list = find_permutations(input_string)
print(permutations_list)

Output

['abc', 'acb', 'bac', 'bca', 'cab', 'cba']

Explanation

In this program, the find_permutations function takes a string as input. It uses the permutations() function from the itertools module to generate all the permutations of the string. 

The result is a list of tuples, where each tuple represents a permutation.

To convert each permutation tuple back into a string, a list comprehension is used. The ''.join(perm) part joins the characters of each tuple into a single string. The resulting list of strings is then returned.

Python Course

String Permutations in Python Without itertools

Here's an approach to find all permutations of a string without using the itertools module. This solution uses a recursive function to generate the permutations:

Code

def find_permutations(string):
    if len(string) == 0:
        return []

    if len(string) == 1:
        return [string]

    permutations = []
    for i in range(len(string)):
        char = string[i]
        remaining_chars = string[:i] + string[i+1:]
        sub_permutations = find_permutations(remaining_chars)
        for sub_permutation in sub_permutations:
            permutations.append(char + sub_permutation)

    return permutations

# Example usage
input_string = "abc"
permutations_list = find_permutations(in

Output

['abc', 'acb', 'bac', 'bca', 'cab', 'cba']

Explanation

In this program, the find_permutations function takes a string as input. It handles two base cases: when the string is empty or has only one character. In these cases, it returns an empty list or a list containing the string itself.

For strings with two or more characters, the function follows a recursive approach. It iterates over each character of the string and considers it as the first character of the permutation. 

The remaining characters are obtained by removing the current character from the string. The function recursively calls itself with the remaining characters and obtains the sub-permutations.

Finally, the function combines the current character with each sub-permutation to form the permutations and adds them to the result list.