Sort a List Without Modifying the Original in Python

To sort a list without modifying the original, you can use the sorted() function in Python. This function returns a new sorted list while keeping the original list unchanged.

Examples

1. Using sorted() to Sort a List Without Modifying the Original

The sorted() function returns a new list that is sorted, leaving the original list unmodified.

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# Original list
numbers = [5, 2, 9, 1, 5, 6]

# Sorting without modifying the original list
sorted_numbers = sorted(numbers)

# Printing both lists
print("Original List:", numbers)
print("Sorted List:", sorted_numbers)

In this example, we:

  1. Define an original list called numbers that contains unsorted values.
  2. Use the sorted() function to create a new sorted list called sorted_numbers.
  3. Print both lists to verify that the original list remains unchanged.

The sorted() function does not alter the numbers list; it simply returns a new list with sorted elements.

Output:

Original List: [5, 2, 9, 1, 5, 6]
Sorted List: [1, 2, 5, 5, 6, 9]

2. Sorting in Descending Order Without Modifying the Original

By passing the reverse=True argument to sorted(), we can sort the list in descending order.

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# Original list
numbers = [3, 8, 1, 7, 4]

# Sorting in descending order without modifying the original list
sorted_descending = sorted(numbers, reverse=True)

# Printing both lists
print("Original List:", numbers)
print("Sorted List (Descending):", sorted_descending)

Here, we:

  1. Use the sorted() function with the reverse=True parameter.
  2. Create a new list sorted_descending that holds the sorted values in descending order.
  3. Verify that the original list remains unchanged by printing it.

The reverse=True argument ensures that the sorting is done in descending order.

Output:

Original List: [3, 8, 1, 7, 4]
Sorted List (Descending): [8, 7, 4, 3, 1]

3. Sorting a List of Strings Without Modifying the Original

We can use sorted() to sort a list of strings alphabetically while keeping the original list unchanged.

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# Original list of strings
words = ["banana", "apple", "cherry", "date"]

# Sorting alphabetically without modifying the original list
sorted_words = sorted(words)

# Printing both lists
print("Original List:", words)
print("Sorted List:", sorted_words)

In this example, we:

  1. Create an unsorted list of strings named words.
  2. Use sorted() to create a new alphabetically sorted list called sorted_words.
  3. Print both lists to confirm that the original remains unchanged.

Output:

Original List: ['banana', 'apple', 'cherry', 'date']
Sorted List: ['apple', 'banana', 'cherry', 'date']

Conclusion

To sort a list without modifying the original, the best approach is to use the sorted() function. It:

  1. Returns a new sorted list while preserving the original.
  2. Allows sorting in ascending or descending order using the reverse=True parameter.
  3. Works with numbers, strings, and other sortable data types.