Control Flow & Data Structures Recap

In Python, logic and data go hand in hand. You need both to write useful programs.

This lesson ties together what you’ve learned about control flow (like if, for, and while) and data structures (like lists, sets, and dictionaries).

We won’t go deep into syntax here — instead, we’ll talk about how to think with these tools.

Python lets you describe what to do (like loop or make a choice) and what to do it with (like lists or dictionaries).

This is where programming becomes flexible:

• You decide which data structure fits your task
• Then, you use logic to interact with that data in meaningful ways

Example: Want to find students who passed?

• Use a dict to store names and scores
• Use a for loop to go through each one
• Use an if to check if the score is high enough

Let’s combine both skills:

Copy
grades = {"Alina": 88, "Mike": 76, "John": 91}

for name, score in grades.items():
    if score >= 85:
        print(name, "did well!")
    else:
        print(name, "needs improvement.")

What’s happening?

• We loop through each name and score
• Use if to separate high vs. low scores
• Output custom messages for each student

When writing real Python scripts, you’ll always use control flow and data structures together.

This is the foundation for:

• Data analysis
• Automation
• Decision engines
• Interactive tools

You’re now ready to test your understanding with a mid-level quiz. Let’s go!