remove even numbers in python

To remove even numbers from a list in Python, you can use a loop to iterate over the list and a conditional statement to check if the current number is even. If it is, you can remove it from the list using the remove method.

main.py
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

for number in numbers:
    if number % 2 == 0:
        numbers.remove(number)

print(numbers)
137 chars
8 lines

In this code, we have a list of numbers from 1 to 10. We use a for loop to iterate over each number in the list. Inside the loop, we use the modulo operator % to check if the current number is even. If the remainder of dividing the number by 2 is 0, that means it's even, so we use the remove method to remove it from the list.

Note that we cannot iterate over the list and remove elements from it at the same time using remove. This is because when we remove an element from the list, the indexes of the remaining elements change, and we might skip or repeat some elements in the iteration. Therefore, in the code above, the loop only runs half as many times as it would otherwise. If you want to remove all even numbers from a list in a more efficient way, one option is to create a new list that only contains the odd numbers:

main.py
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
odd_numbers = []

for number in numbers:
    if number % 2 != 0:
        odd_numbers.append(number)

print(odd_numbers)
162 chars
9 lines

In this code, we create an empty list odd_numbers to store the odd numbers. We use a for loop to iterate over each number in the original list, and if the number is odd (i.e., the remainder of dividing it by 2 is not 0), we append it to the odd_numbers list. Finally, we print the odd_numbers list using the print function. This approach is more efficient than removing elements from the original list, especially for larger lists, since we avoid the need to repeatedly resize the list during the removal process.