Accessing Dictionary Items in Python

Dictionaries in Python are versatile data structures that store data in key-value pairs. This guide explains how to access items in a dictionary.

Key Concepts

• Dictionary: A collection of key-value pairs, where each key is unique and is used to access its corresponding value.
• Syntax: A dictionary is defined using curly braces {} and can be created using the dict() function.

python
# Example of a dictionary
my_dict = {
    'name': 'Alice',
    'age': 30,
    'city': 'New York'
}

Accessing Dictionary Items

You can access items in a dictionary using the following methods:

1. Using Square Brackets

• You can access a value by referring to its key inside square brackets.

python
# Accessing value using square brackets
name = my_dict['name']  # Output: 'Alice'

2. Using the get() Method

• The get() method allows you to access values without raising an error if the key does not exist. It returns None or a specified default value instead.

python
# Accessing value using get() method
age = my_dict.get('age')           # Output: 30
unknown = my_dict.get('country')   # Output: None
unknown_with_default = my_dict.get('country', 'Not Found')  # Output: 'Not Found'

Iterating Through Dictionary Items

You can loop through a dictionary to access keys, values, or both.

1. Looping Through Keys

python
# Looping through keys
for key in my_dict:
    print(key)  # Output: name, age, city

2. Looping Through Values

python
# Looping through values
for value in my_dict.values():
    print(value)  # Output: Alice, 30, New York

3. Looping Through Key-Value Pairs

python
# Looping through key-value pairs
for key, value in my_dict.items():
    print(f"{key}: {value}")
    # Output: 
    # name: Alice
    # age: 30
    # city: New York

Summary

• Dictionaries are used to store data in key-value pairs.
• You can access items using square brackets or the get() method.
• You can iterate through keys, values, or both to access dictionary content.

Understanding these basic operations will help you effectively work with dictionaries in Python!