List#

Python List functions like an array, with much more power and flexibility like holding multiple types of variables, dynamic allocation, etc. Lists could be created using square brackets:

[1, 2, 3]
["Code", "the", "dream"]
[1, "one", 2, "two", 3, "three"]

List operations#

  1. Access and update by index

fruits = ["apple", "banana", "cherry"]
#                      ^
#            0         1         2

fruits[1] will return the value at the index 1 - the string “banana”.

In Python, you could access the trailing element using negative index e.g. to get cherry, use fruits[-1]

fruits = ["apple", "banana", "cherry"]
#                                ^
#           -3        -2        -1

  1. Insert

The list.append method adds an item to the end of the list:

fruits = ["apple", "banana", "cherry"]
fruits.append("mango")

The list.insert method insert an item to the given index

fruits.insert(1, "watermelon")

  1. Remove

You can remove items from a list using several methods:

  • list.remove(value) removes the first matching value:

fruits = ["apple", "banana", "cherry"]
fruits.remove("banana")

  • list.pop(index) removes and returns the item at the given index (default is the last item):

fruits.pop()  # Removes "cherry"
fruits.pop(0)  # Removes "apple"

  • del deletes an item by index:

del fruits[1]  # Deletes apple

  • list.clear method empties the list

  1. List slicing

List slicing allows you to extract a portion (or “slice”) of a list using the start:stop:step syntax.

numbers: list[int] = [10, 20, 30, 40, 50]
slice_1: list[int] = numbers[1:4]  # [20, 30, 40]

More list operations?#

Python provides a comprehensive set of methods for working with lists, documented in the official List API documentation

You can also access documentation offline using the built-in pydoc tool, or through code editors and IDEs that provide inline docs using the Python source code & LSP.

python -m pydoc list.append

Help on method_descriptor in list:

list.append = append(self, object, /) unbound builtins.list method
    Append object to the end of the list.

You’ll explore more list operations and methods through hands-on problem sets.