Python: Create all possible permutations from a given collection of distinct numbers

Last update on May 24 2025 10:47:38 (UTC/GMT +8 hours)

List Permutations Generator

Write a Python program that generates a list of all possible permutations from a given collection of distinct numbers.

Visual Presentation:

Sample Solution:

Python Code:

# Define a function 'permute' that generates all permutations of a list of numbers.
def permute(nums):
    # Initialize the result list with an empty permutation.
    result_perms = [[]]

    # Iterate through each number in the input list.
    for n in nums:
        # Create a new list to store permutations with the current number.
        new_perms = []

        # Iterate through each existing permutation in the result list.
        for perm in result_perms:
            # Insert the current number at different positions within each existing permutation.
            for i in range(len(perm)+1):
                new_perms.append(perm[:i] + [n] + perm[i:])

        # Update the result list with the new permutations.
        result_perms = new_perms

    # Return the final list of permutations.
    return result_perms

# Create a list of numbers.
my_nums = [1, 2, 3]

# Print the original collection and the collection of distinct numbers.
print("Original Collection: ", my_nums)
print("Collection of distinct numbers:\n", permute(my_nums))

Sample Output:

Original Cofllection:  [1, 2, 3]
Collection of distinct numbers:
 [[3, 2, 1], [2, 3, 1], [2, 1, 3], [3, 1, 2], [1, 3, 2], [1, 2, 3]]

Explanation:

This above Python code defines a function called "permute()" that generates all permutations of a list of numbers. Here's a brief explanation:

• The function "permute()" takes a list of numbers ('nums') as input.
• It initializes a list 'result_perms' with an empty permutation to store the final results.
• It iterates through each number in the input list.
• For each number, it creates a new list ('new_perms') to store permutations with the current number.
• It iterates through each existing permutation in the result list.
• For each existing permutation, it inserts the current number at different positions to create new permutations.
• It updates the 'result_perms' list with the new permutations.
• The function returns the final list of permutations.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to generate all permutations of a list of numbers where repetition is allowed.
• Write a Python program to generate all permutations of the characters in a given string.
• Write a Python program to generate all partial permutations (of length k) from a list of distinct numbers.
• Write a Python program to compute the next lexicographic permutation for a given list of numbers.

Go to:

• Python Basic Exercises Home ↩
• Python Exercises Home ↩

Previous: Write a Python program to check the sum of three elements (each from an array) from three arrays is equal to a target value. Print all those three-element combinations.
Next: Write a Python program to get all possible two digit letter combinations from a digit (1 to 9) string.

Python Code Editor :

Have another way to solve this solution? Contribute your code (and comments) through Disqus.