Accessing Dictionary Keys

To access the keys of a dictionary in Python, you can use the keys() method. This returns a view object that displays all the keys in the dictionary.


              12345678
            
book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}
keys = book.keys()
print(keys)  # Output: dict_keys(['title', 'author', 'year', 'genre'])

Iterating Through Keys

You can iterate through the keys in a dictionary using a for loop:


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book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}

for key in book.keys():
    print(key)

Checking for the Existence of a Key

Use the in keyword to check if a specific key exists in the dictionary:


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book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}

if "author" in book:
    print("The 'author' key exists in the dictionary.")

Task

Swipe to start coding

You are given a dictionary authors_books, where the key is the author and the value is a list of their book titles.

Your goal:

Initialize the variable keys as a list of the dictionary keys.
Initialize the variable all_books as a list of all available book titles.
Use a for loop to get the book lists by author.
Use a nested for loop and the append() method to fill the all_books list with all available books.

Solution

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Section 2. Chapter 3

Accessing Dictionary Keys

To access the keys of a dictionary in Python, you can use the keys() method. This returns a view object that displays all the keys in the dictionary.


              12345678
            
book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}
keys = book.keys()
print(keys)  # Output: dict_keys(['title', 'author', 'year', 'genre'])

Iterating Through Keys

You can iterate through the keys in a dictionary using a for loop:


              123456789
            
book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}

for key in book.keys():
    print(key)

Checking for the Existence of a Key

Use the in keyword to check if a specific key exists in the dictionary:


              123456789
            
book = {
    "title": "Pride and Prejudice",
    "author": "Jane Austen",
    "year": 1813,
    "genre": "Romance"
}

if "author" in book:
    print("The 'author' key exists in the dictionary.")

Task

Swipe to start coding

You are given a dictionary authors_books, where the key is the author and the value is a list of their book titles.

Your goal:

Initialize the variable keys as a list of the dictionary keys.
Initialize the variable all_books as a list of all available book titles.
Use a for loop to get the book lists by author.
Use a nested for loop and the append() method to fill the all_books list with all available books.

Solution

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Everything was clear?

Thanks for your feedback!

Section 2. Chapter 3

Switch to desktop for real-world practiceContinue from where you are using one of the options below

Python Data Structures

Accessing Dictionary Keys

Iterating Through Keys

Checking for the Existence of a Key

Solution

Accessing Dictionary Keys

Iterating Through Keys

Checking for the Existence of a Key

Solution