Lists and Tuples

Lists and tuples are Python's primary sequence types. A list is a mutable, ordered collection of items. A tuple is similar but immutable — once created, it cannot be changed. Understanding when to use each is a key part of writing effective Python.

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Creating Lists

# A list of integers
numbers = [1, 2, 3, 4, 5]

# A list of strings
fruits = ["apple", "banana", "cherry"]

# A mixed list
mixed = [42, "hello", 3.14, True, None]

# An empty list
empty = []

# List from range
digits = list(range(10))
print(digits)  # [0, 1, 2, 3, 4, 5, 6, 7, 8, 9]

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Accessing Elements

fruits = ["apple", "banana", "cherry", "date", "elderberry"]

print(fruits[0])    # apple — first element
print(fruits[-1])   # elderberry — last element
print(fruits[1:3])  # ['banana', 'cherry'] — slice
print(fruits[:2])   # ['apple', 'banana'] — first two
print(fruits[3:])   # ['date', 'elderberry'] — from index 3 onwards
print(fruits[::2])  # ['apple', 'cherry', 'elderberry'] — every other

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Modifying Lists

Lists are mutable — you can change them after creation:

fruits = ["apple", "banana", "cherry"]

# Change an element
fruits[1] = "blueberry"
print(fruits)  # ['apple', 'blueberry', 'cherry']