Mastering Dictionary Data Structure in Python | Real-World Coding Examples

🔥 Welcome to another Python tutorial! In this video, we will dive into Dictionaries in Python, one of the most powerful data structures used to store key-value pairs efficiently. Dictionaries allow you to store and retrieve data quickly and meaningfully, making them ideal for applications that require fast lookups and structured data storage.

📌 What You’ll Learn in This Video:
✅ What is a Dictionary in Python?
✅ How to create and modify dictionaries
✅ Accessing, adding, and removing key-value pairs
✅ Looping through dictionaries
✅ Using Dictionary Comprehension for efficiency
✅ Real-world practical coding examples

📌 What is a Dictionary in Python?
A dictionary in Python is a collection of key-value pairs. It is an unordered, mutable, and indexed data structure that allows fast lookups and modifications.

📌 Key Features of Dictionaries:
✔ Stores data in key-value pairs
✔ Fast lookups (O(1) time complexity)
✔ Keys must be unique
✔ Supports dynamic modifications

💻 Real-World Coding Examples

1️⃣ Creating a Dictionary

# Create a dictionary of student information
student_info = {
"name": "Sopheap",
"age": 20,
"grade": "A",
"courses": ["Math", "Physics", "English"]
}

# Create an empty dictionary
empty_dict = {}

print(f"student_info = {student_info}")
print(f"empty_dict = {empty_dict}")

🔹 Dictionaries use {} to define key-value pairs.
🔹 Keys are unique and can be of any immutable data type (e.g., strings, numbers).

2️⃣ Accessing Values by Key

print(f'student_info["name"] = {student_info["name"]}')
print(f'student_info["courses"] = {student_info["courses"]}')

🔹 Access values using dictionary[key].
🔹 If the key does not exist, Python will raise a KeyError.

3️⃣ Modifying Dictionary Values

# Modifying a value in the dictionary
student_info["age"] = 21
print(f'student_info["age"] = {student_info["age"]}')

🔹 Dictionaries are mutable, meaning you can update values easily.

4️⃣ Adding a New Key-Value Pair

# Adding a new key-value pair
student_info["gender"] = "Female"
print(f'student_info["gender"] = {student_info["gender"]}')

print(f"student_info = {student_info}")

🔹 Adding a new key-value pair to a dictionary is as simple as assigning a value to a new key.

5️⃣ Removing a Key-Value Pair

# Removing a key-value pair
print(f"Grade removed is: {removed_grade}")

print(f"student_info = {student_info}")

🔹 The .pop() method removes a key and returns its value.
🔹 If the key does not exist, Python will raise a KeyError.

6️⃣ Checking if a Key Exists in Dictionary

is_present = "grade" in student_info
print(f"grade key is: {is_present}")

🔹 The in keyword checks if a key exists in the dictionary.

7️⃣ Looping Through a Dictionary

# Looping through keys
for key in student_info:
print(key, end="\t\t")

print()
# Looping through values
print(value, end="\t\t")

print()
✔ Looping through keys gives all dictionary keys.
✔ Looping through values extracts all dictionary values.

8️⃣ Dictionary Comprehension

# Dictionary comprehension to create a new dictionary
squared_dict = {x: x**2 for x in range(1, 10)}
print(f'squared_dict = {squared_dict}')

🔹 Dictionary comprehension allows creating new dictionaries efficiently!

📌 Why Use Dictionaries?
✔ Fast lookups (compared to lists)
✔ Organized data structure for quick access
✔ Flexible & scalable for complex applications
✔ Great for storing structured data like JSON

🚀 Conclusion
Dictionaries in Python are an essential data structure that allow us to store and retrieve data efficiently. They are widely used in data processing, APIs, databases, and real-world applications.

🎯 Key Takeaways:
✅ Key-value pairs allow meaningful data storage.
✅ Fast lookup times compared to lists.
✅ Mutable (values can be updated dynamically).
✅ Perfect for structured data representation.

🎥 Watch the full tutorial and start using dictionaries in your Python programs today!

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