Dictionaries in Python

Dictionaries are mutable, unordered collections of key-value pairs in Python. They are defined using curly braces and allow for fast access to values based on their corresponding keys.

Creating a Dictionary

You can create a dictionary by enclosing key-value pairs in curly braces. Each key is separated from its value by a colon, and pairs are separated by commas.

Example of Creating a Dictionary

# Creating a dictionary
        my_dict = {
            "name": "Alice",
            "age": 30,
            "city": "New York"
        }
        print("Dictionary created:", my_dict)

Output

Dictionary created: {'name': 'Alice', 'age': 30, 'city': 'New York'}

Accessing Values in a Dictionary

You can access values in a dictionary by using the key in square brackets. If the key does not exist, a KeyError will be raised.

Example of Accessing Values

# Accessing values in a dictionary
        name = my_dict["name"]
        age = my_dict["age"]
        print("Name:", name)
        print("Age:", age)

Output

Name: Alice
Age: 30

Adding and Updating Values in a Dictionary

You can add a new key-value pair to a dictionary by assigning a value to a new key. To update an existing value, simply assign a new value to the existing key.

Example of Adding and Updating Values

# Adding a new key-value pair
        my_dict["email"] = "alice@example.com"
        print("After adding email:", my_dict)
        
        # Updating an existing value
        my_dict["age"] = 31
        print("After updating age:", my_dict)

Output

After adding email: {'name': 'Alice', 'age': 30, 'city': 'New York', 'email': 'alice@example.com'}
After updating age: {'name': 'Alice', 'age': 31, 'city': 'New York', 'email': 'alice@example.com'}

Conclusion

Dictionaries in Python provide a powerful way to store and manage key-value pairs. You can easily create, access, add, and update values in dictionaries, making them versatile data structures for various applications.