Coding Bubble Sort in Python

def bubblesort(my_list):

    # Outer loop for number of passes

    for i in range(len(my_list) – 1, 0, -1):

        # Inner loop for comparisons in each pass

        for j in range(i):

            # Compare adjacent items

            if my_list[j] > my_list[j + 1]:

                # Swap if items are out of order

                temp = my_list[j]

                my_list[j] = my_list[j + 1]

                my_list[j + 1] = temp

    return my_list

Step 2: Understanding the Loops

• Outer loop (i): Determines the number of passes.

  • First pass: len(my_list) - 1 comparisons

  • Second pass: len(my_list) - 2 comparisons

  • And so on… until the list is sorted.

• Inner loop (j): Goes through the list up to the last unsorted element.

• Swap logic: If the current element is greater than the next, swap them using a temporary variable.

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Step 3: Step-by-Step Example

Original list: [2, 6, 5, 1, 3, 4]

First pass:

• Compare 2 and 6 → no swap → [2, 6, 5, 1, 3, 4]

• Compare 6 and 5 → swap → [2, 5, 6, 1, 3, 4]

• Compare 6 and 1 → swap → [2, 5, 1, 6, 3, 4]

• Compare 6 and 3 → swap → [2, 5, 1, 3, 6, 4]

• Compare 6 and 4 → swap → [2, 5, 1, 3, 4, 6]

Second pass:

• Compare 2 and 5 → no swap → [2, 5, 1, 3, 4, 6]

• Compare 5 and 1 → swap → [2, 1, 5, 3, 4, 6]

• Compare 5 and 3 → swap → [2, 1, 3, 5, 4, 6]

• Compare 5 and 4 → swap → [2, 1, 3, 4, 5, 6]

Third pass:

• Compare 2 and 1 → swap → [1, 2, 3, 4, 5, 6]

• Compare 2 and 3 → no swap

• Compare 3 and 4 → no swap

Fourth pass:

• Compare 1 and 2 → no swap

• Compare 2 and 3 → no swap

List is now sorted: [1, 2, 3, 4, 5, 6]

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Step 4: Running the Function

Output:

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Key Points

• Bubble Sort compares adjacent elements and swaps if necessary.

• Largest items “bubble up” to the end in each pass.

• Time Complexity:

  • Worst-case: O(n²)

  • Best-case: O(n) (if already sorted)

• Space Complexity: O(1) (in-place sorting)