Adding, Changing and Removing Items

Lists can change

Unlike strings, lists are mutable: you can change them after creating them.

Changing an item

colours = ["red", "green", "blue"]
colours[1] = "yellow"
print(colours)

Output

['red', 'yellow', 'blue']

Adding items

tasks = ["wake up", "brush teeth"]
tasks.append("eat breakfast")
print(tasks)
tasks.insert(0, "alarm rings")
print(tasks)

Output

['wake up', 'brush teeth', 'eat breakfast']
['alarm rings', 'wake up', 'brush teeth', 'eat breakfast']

• append(x) adds x to the end.
• insert(i, x) puts x at position i and moves the rest along.

Removing items

pets = ["cat", "dog", "fish", "dog"]
pets.remove("dog")
print(pets)

last = pets.pop()
print("Removed:", last)
print(pets)

del pets[0]
print(pets)

Output

['cat', 'fish', 'dog']
Removed: dog
['cat', 'fish']
['fish']

Common mistake: remove("kiwi") gives an error if kiwi isn't in the list. Check with in first.