Introduction to Python Dictionaries: Concepts, Usage, and Examples

Master Python data types with this comprehensive guide. Learn about numeric, string, boolean, and collection data types with examples, exercises, and tasks. Perfect for beginners and professionals to enhance their Python programming skills.

In Python, a dictionary is a collection of key-value pairs. Each key in a dictionary is unique, and it is associated with a value. Dictionaries are used to store data values like a map or a real-life dictionary where each word (key) has a definition (value). They are mutable, meaning you can change, add, or remove items after the dictionary is created.

Creating a Dictionary

You create a dictionary using curly braces {} with keys and values separated by a colon :. Multiple key-value pairs are separated by commas.

# Example of a dictionary
student = {
    "name": "John",
    "age": 20,
    "courses": ["Math", "Science"]
}

Accessing Values

You can access the value associated with a specific key by using square brackets [] or the get() method.

# Accessing values
print(student["name"])  # Output: John
print(student.get("age"))  # Output: 20

Adding or Updating Elements

You can add a new key-value pair or update an existing one by assigning a value to the key.

# Adding a new key-value pair
student["grade"] = "A"

# Updating an existing value
student["age"] = 21

Task 12: Creating a Dictionary

Write a Python program that:

• Creates a dictionary with two items (name and age).
• Prints the dictionary.
• Prints only the name from the dictionary.

Example Output:

Person: {'name': 'Alice', 'age': 25}
Name: Alice

Task 13: Adding to a Dictionary

Write a Python program that:

• Creates a dictionary with name and country.
• Adds a new key “hobby” with a value.
• Prints the updated dictionary.

Example Output:

Original Dictionary: {'name': 'John', 'country': 'USA'}
Updated Dictionary: {'name': 'John', 'country': 'USA', 'hobby': 'Reading'}

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