How do I filter lists in Python in pure Python?

Filtering lists in Python can be done using various techniques, primarily using list comprehensions, the `filter()` function, or simple loops. Below are some examples demonstrating how to filter lists effectively using pure Python techniques.

        
# Example of filtering a list of numbers to get only even numbers

# Using list comprehension
numbers = [1, 2, 3, 4, 5, 6]
even_numbers = [num for num in numbers if num % 2 == 0]
print(even_numbers)  # Output: [2, 4, 6]

# Using filter function
even_numbers = list(filter(lambda x: x % 2 == 0, numbers))
print(even_numbers)  # Output: [2, 4, 6]

# Using a for loop
even_numbers = []
for num in numbers:
    if num % 2 == 0:
        even_numbers.append(num)
print(even_numbers)  # Output: [2, 4, 6]