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Iterating Lists

Lists are ordered, mutable collections that can store any type of data. In Python, we can find the length of a list using len(list_name).

List Basics​

If we are coming from C, think of lists as super-charged arrays. They handle resizing automatically and can store mixed data types.

# Type hinting: specify the element type(s) inside list[]
# See: [Modern Python Types](../1 - basics/1.9 - modern-python-types.md) for details
tech_stack: list[str | float] = ["Python", 3.12, "Bash"]

# Adding items to the end
tech_stack.append("C")

# Removing and returning the last item
last_added = tech_stack.pop()

print(tech_stack)
print(f"Removed: {last_added}")

Output:

['Python', 3.12, 'Bash']
Removed: C

Iteration​

We can loop through a list directly. This is the Pythonic way compared to using index-based counters or manual incrementing.

ingredients = ["ginger", "cardamom", "cloves"]

for spice in ingredients:
    print(f"Adding {spice}...")

Output:

Adding ginger...
Adding cardamom...
Adding cloves...

Worth Mentioning: Useful Methods​

  • insert(index, item): Adds an item at a specific position.
  • remove(item): Removes the first occurrence of a value.
  • extend(collection): Appends all items from another collection.
  • sort(): Sorts the list in place.