Python: Remove and print every third number from a list of numbers until the list becomes empty

Last update on April 17 2025 13:06:07 (UTC/GMT +8 hours)

Remove Every Third

Write a Python program that removes and prints every third number from a list of numbers until the list is empty.

Visual Presentation:

Sample Solution:

Python Code:

# Define a function named 'remove_nums' that takes a list 'int_list' as a parameter.
def remove_nums(int_list):
    # Set the starting position for removal to the 3rd element (0-based index).
    position = 3 - 1
    # Initialize the index variable to 0.
    idx = 0
    # Get the length of the input list.
    len_list = len(int_list)
    
    # Continue removing elements until the list is empty.
    while len_list > 0:
        # Calculate the new index based on the starting position and current index.
        idx = (position + idx) % len_list
        # Print and remove the element at the calculated index.
        print(int_list.pop(idx))
        # Decrement the length of the list.
        len_list -= 1

# Create a list of numbers.
nums = [10, 20, 30, 40, 50, 60, 70, 80, 90]

# Call the 'remove_nums' function with the list of numbers.
remove_nums(nums)

Sample Output:

30
60
90
40
80
50
20
70
10

Explanation:

The above code defines a function "remove_nums()" that takes a list as input. It removes and prints elements from the list in a specific pattern until the list is empty. The pattern starts from the 3rd element and removes every 3rd element thereafter. The code then calls this function with a list of numbers and prints the removed elements.

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to remove every nth element from a list until the list is empty, where n is input by the user.
• Write a Python program simulating a circular elimination game where every third person is removed until one remains.
• Write a Python program that alternates between removing the second and third elements from a list until it is empty.
• Write a Python program that repeatedly removes an element positioned at (current element value modulo current list length) until no elements remain.

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