Python lists

Summary of “Python lists” Video

Main Ideas and Concepts

• Introduction to Python lists as a new data type.
• Lists are collections of items enclosed in square brackets [].
• Lists can hold multiple values of any type and do not need to be ordered.
• Indexing in lists starts at zero.
• Lists are mutable, meaning their elements can be changed.
• The length of a list can be found using the len() function.
• Iterating through lists can be done using loops, specifically for loops.
• Different methods of iterating through lists:
  • Using for i in range(len(my_list)) to iterate by index.
  • Using for value in my_list to iterate directly over values.
  • Using enumerate() to get both index and value during iteration.
• Introduction to list comprehension as a concise way to iterate and process lists.
• Practical note: lists will be used later to hold objects, such as LED objects in MicroPython.

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Detailed Methodology / Instructions

Creating a list

my_list = []  # empty list
my_list = [2, 6, 8, 15, 4]  # list with values

Accessing elements by index

print(my_list[0])  # prints 2 (first element)
print(my_list[2])  # prints 8 (third element)

Changing elements

my_list[3] = 16  # replaces 15 with 16 at index 3

Getting list length

length = len(my_list)  # returns 5 for this example

Iterating through a list by index

for i in range(len(my_list)):
    print(i)  # prints indices 0 through 4

Iterating through list values directly

for value in my_list:
    print(value)  # prints each value in the list

Iterating with index and value using enumerate()

for index, value in enumerate(my_list):
    print(index, value)

Using list comprehension for printing values

print([x for x in my_list])

Note: This creates a new list and prints it; not always the simplest or clearest method for beginners.

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Speakers / Sources

• Single speaker / instructor (name not provided), presenting and coding live in VS Code.
• No other speakers or sources featured.