In Python, how do I Index a list with another list?

Indexing a list with another list in Python allows you to retrieve multiple elements from the original list based on the indices specified in the second list. Here’s how it works conceptually:

1. Basic Concept

• You have two lists:
  • Source List: The list you want to extract elements from.
  • Index List: A list of integers representing the indices to retrieve.
• For each integer in the index list, retrieve the element at that position in the source list.

2. Steps to Index a List with Another List

1. Iterate over the index list.
2. For each index, retrieve the corresponding element from the source list.
3. Collect the results in a new list.

Example Workflow Without Code:

Imagine you have:

• A source list: [10, 20, 30, 40, 50].
• An index list: [1, 3].

You would:

1. Look at the first index (1) and retrieve the second element (20).
2. Look at the second index (3) and retrieve the fourth element (40).
3. Combine the results into a new list: [20, 40].

This process can be implemented directly or using list comprehensions for simplicity.