PYTHON
Flatten a Nested List Using List Comprehension
Learn a concise and Pythonic way to flatten a list of lists into a single, one-dimensional list using a simple list comprehension, ideal for data processing.
# Example of a nested list
nested_list = [[1, 2, 3], [4, 5], [6, 7, 8, 9]]
# Flatten the list using a nested list comprehension
flattened_list = [item for sublist in nested_list for item in sublist]
print(f"Flattened list: {flattened_list}")
# Flattening with a condition (e.g., only even numbers)
conditional_flatten = [item for sublist in nested_list for item in sublist if item % 2 == 0]
print(f"Conditional flatten (evens): {conditional_flatten}")
How it works: This snippet demonstrates how to flatten a list of lists into a single list using a nested list comprehension. This Pythonic construct iterates through each `sublist` in the `nested_list`, and then through each `item` within that `sublist`, effectively collecting all items into a new, flat list. It's a clean and efficient way to handle common data transformation tasks, and can also incorporate conditions for filtering.