Python chapters

Chapter 8 of 17

Loops

Try this in our Python 3 Compiler →

Repeating work

Loops let you run the same block of code many times — once per item in a list, once per character in a string, or until a condition becomes false. They are how you process collections of data without writing the same line a hundred times.

```python
for i in range(5):
    print("i =", i)

n = 0 while n < 3: n += 1 ```

for vs while

Use a for loop when you know up-front how many times to iterate or you are walking through a collection. Use while when you have to keep going until some condition is met — for example, reading lines from a file until the end is reached.

break and continue

break stops a loop immediately and continue skips to the next iteration. Use them to handle early exit conditions, but avoid burying them deep inside a complex loop — that makes flow hard to follow.

Try it yourself

Python 3 Compiler
Output
Code runs on the Play with Coding execution engine — your code is saved locally for next time.