Dictionary Methods and Nesting

Dictionaries in Python become especially powerful when you start using built-in methods and nesting structures inside them.

These techniques help you organize, update, and safely access complex data — a key skill in data analysis.

Built-in methods allow you to interact with dictionary data efficiently.

For example:

• .get() safely retrieves a value, even if the key might not exist.
• .update() adds or modifies key-value pairs.
• .pop() removes entries without needing to access them directly.

These tools reduce bugs and improve readability in your code.

Nesting means placing one data structure inside another — like a dictionary inside another dictionary.

This is useful when you want to represent complex or grouped information, like multiple subjects and scores for each student.

Let’s walk through an example step by step.

Copy
# Create a nested dictionary for a student
student = {
    "name": "Alina",
    "grades": {
        "math": 88,
        "history": 92
    }
}

# Safely access a nested value
math_score = student["grades"].get("math", 0)
print("Math Score:", math_score)  # Output: 88

• We first define a dictionary student that includes another dictionary inside the grades key.

• The .get("math", 0) method tries to access the "math" score.

  • If "math" exists, it returns the score (88).
  • If not, it would return the default value 0 to prevent errors.

• This is helpful when you work with real-world data that might be incomplete.

Now that you can build and modify nested structures, we’ll move on to making decisions in code using if, elif, and else.