For Loop
Also known as: for, count-controlled loop
A control structure that repeats a block of code a specific number of times or for each item in a collection. For loops are the most common loop type.
💡 Intuition
A for loop is like 'do this for each...' — for each student in the class, print their name. For each number from 1 to 10, add it to the total.
Core Idea
For loops are best when you know how many times to repeat or when iterating over a collection. The loop variable takes each value automatically.
🔬 Example
🎯 Why It Matters
For loops are the most common loop type. Processing lists, arrays, and ranges almost always uses a for loop.
⚠️ Common Confusion
range(5) gives 0 to 4, not 1 to 5. Off-by-one errors are the most common for-loop bug.
Related Concepts
Prerequisites
Next Steps
How For Loop Connects to Other Ideas
To understand for loop, you should first be comfortable with iteration and while loop. Once you have a solid grasp of for loop, you can move on to array.
Go Deeper
Frequently Asked Questions
What is For Loop in CS Thinking?
A control structure that repeats a block of code a specific number of times or for each item in a collection.
Why is For Loop important?
For loops are the most common loop type. Processing lists, arrays, and ranges almost always uses a for loop.
What do students usually get wrong about For Loop?
range(5) gives 0 to 4, not 1 to 5. Off-by-one errors are the most common for-loop bug.
What should I learn before For Loop?
Before studying For Loop, you should understand: iteration, while loop.