Python

Dictionaries In Python

Adarsh Dabral's photo
Adarsh Dabral
·

2 min read

Introduction: Dictionaries in Python is one of the best thing. Don't worry if you're not sure what they are yet; we'll explain everything in simple terms.

What are Dictionaries? Imagine you have a real dictionary book. In Python, a dictionary is like that, but instead of words and their meanings, you have pairs of information called "key-value pairs".

Creating a Dictionary: Creating a dictionary in Python is easy! You can make one using curly braces {} or the dict() function. Let's see:

pythonCopy code# Creating a dictionary with curly braces
my_dict = {'name': 'Alice', 'age': 30}

# Creating a dictionary with dict() function
another_dict = dict(city='New York', country='USA')

Accessing and Modifying Dictionary Elements: To get information from a dictionary, you use the keys. For example:

pythonCopy codeprint(my_dict['name'])  # Output: Alice

You can also change values or add new pairs like this:

pythonCopy codemy_dict['age'] = 25  # Changing the value
my_dict['job'] = 'Engineer'  # Adding a new pair

Common Operations on Dictionaries: You can loop through dictionaries and get all keys, values, or both using methods like keys(), values(), and items().

pythonCopy code# Looping through keys
for key in my_dict.keys():
    print(key)

# Looping through values
for value in my_dict.values():
    print(value)

# Looping through both keys and values
for key, value in my_dict.items():
    print(key, value)

Dictionary Comprehensions: Dictionary comprehensions are like shortcuts to create dictionaries in Python. Let's say we want to create a dictionary of numbers and their squares:

pythonCopy codesquares = {num: num*num for num in range(1, 6)}
print(squares)  # Output: {1: 1, 2: 4, 3: 9, 4: 16, 5: 25}

Nested Dictionaries: Sometimes, you might want to have dictionaries inside dictionaries. It's like having folders inside folders on your computer!

pythonCopy codenested_dict = {
    'person1': {'name': 'Bob', 'age': 25},
    'person2': {'name': 'Alice', 'age': 30}
}

Common Pitfalls and Best Practices: Be careful not to use a key that doesn't exist in a dictionary, or Python will give you an error. Also, remember that dictionaries don't have a specific order, so the order of items might not be what you expect.

Conclusion: Congratulations! You now understand the basics of dictionaries in Python. Keep practicing, and soon you'll be using dictionaries like a pro in your Python projects.

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