Working with Lists, Tuples, and Dictionaries in Python

Python provides several built-in data structures that help in storing and manipulating data efficiently. This guide covers lists, tuples, and dictionaries.

Lists in Python

A list is an ordered, mutable collection of elements. Lists allow duplicate values and can store different data types.

Creating a List

fruits = ["apple", "banana", "cherry"]
print(fruits)

Accessing Elements

print(fruits[0])  # Output: apple
print(fruits[-1])  # Output: cherry

Modifying Lists

fruits.append("orange")  # Adds an element
fruits.remove("banana")  # Removes an element
print(fruits)

Looping Through a List

for fruit in fruits:
    print(fruit)

Tuples in Python

A tuple is an ordered, immutable collection of elements. Once created, tuples cannot be modified.

Creating a Tuple

colors = ("red", "green", "blue")
print(colors)

Accessing Tuple Elements

print(colors[1])  # Output: green

Tuple Unpacking

r, g, b = colors
print(r, g, b)  # Output: red green blue

Dictionaries in Python

A dictionary is an unordered collection of key-value pairs. Each key must be unique.

Creating a Dictionary

person = {"name": "Alice", "age": 25, "city": "New York"}
print(person)

Accessing Values

print(person["name"])  # Output: Alice

Modifying a Dictionary

person["age"] = 26  # Updating a value
person["gender"] = "Female"  # Adding a new key-value pair
print(person)

Looping Through a Dictionary

for key, value in person.items():
    print(f"{key}: {value}")

Conclusion

Understanding lists, tuples, and dictionaries is fundamental to mastering Python. Lists provide flexibility, tuples ensure immutability, and dictionaries allow fast key-based data retrieval.

Quiz Questions

1. What is the main difference between a list and a tuple?
2. How do you add an item to a list in Python?
3. Can you modify a tuple after creation? Why or why not?
4. How do you retrieve a value from a dictionary using a key?
5. What method is used to loop through key-value pairs in a dictionary?