Lists
Table of contents
Description
Lists are simply a comma-separated sequence of elements, enclosed by square brackets.
- Mutable: you can change their individual elements.
- Index numbers allow access to individual elements.
- Ordered: the elements are stored in a specific order.
- Many different actions (methods and functions) can be performed on lists.
- Python Docs: Lists, Sequence Types
Example
Indexing
An index is the position of an element in a sequence (like a list). The first element is at index 0. Negative indexing begins at the last element with index -1.
Slicing
A slice is a piece of a sequence. It is defined by a starting index, a (non-inclusive) ending index, and a step value. If any of the three arguments to the slice are missing, the defaults are as follows:
- Start: first character
- End: last character
- Step: 1
| Begin | End + 1 | Step | Code | Result |
|---|---|---|---|---|
| 2 | 4 | flavors[2:4] | ['Gingersnap', 'Molten Lava'] | |
| 3 | flavors[:3] | ['Lemon Glaze', 'Pink Velvet', 'Gingersnap'] | ||
| 1 | flavors[1:] | ['Pink Velvet', 'Gingersnap', 'Molten Lava'] | ||
flavors[:] | ['Lemon Glaze', 'Pink Velvet', 'Gingersnap', 'Molten Lava'] | |||
| -1 | -1 | flavors[-1::-1] | ['Molten Lava', 'Gingersnap', 'Pink Velvet', 'Lemon Glaze'] | |
| 2 | flavors[::2] | ['Lemon Glaze', 'Gingersnap'] |
Mutability
Lists are mutable, which means you can change any of their attributes after instantiation.