Tips & Common Mistakes — break & continue

Mistake 1: Code After break or continue Doesn't Run

# ❌ This print never happens
for i in range(5):
    if i == 3:
        break
        print("This line is unreachable!")  # Never runs!

# ✅ Put the print BEFORE break
for i in range(5):
    if i == 3:
        print("Stopping at 3!")
        break

Rule: Always put any code you want to execute before break or continue.

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Mistake 2: Forgetting to Update the Counter Before continue

# ❌ count never increases for skipped items
count = 0
for item in items:
    if item == "skip_me":
        continue
    count += 1  # This only counts non-skipped items (might be what you want!)

Think about whether your counter should track all iterations or just the non-skipped ones.

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Mistake 3: while True Without a break

# ❌ Infinite loop — no way out!
while True:
    print("Help, I'm stuck!")

# ✅ Always have a break condition
while True:
    answer = do_something()
    if answer == "done":
        break

Rule: Every while True loop must have a break somewhere inside it.

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Mistake 4: Using break When You Meant continue

numbers = [1, -2, 3, -4, 5]

# ❌ Stops at the first negative — only processes [1]
for n in numbers:
    if n < 0:
        break
    print(n)

# ✅ Skips negatives — processes [1, 3, 5]
for n in numbers:
    if n < 0:
        continue
    print(n)

• break = "I'm done with this entire loop"
• continue = "Skip this one, keep going"

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When to Use What

Situation	Use
Searching for something, stop when found	break
Filtering items, skip some but keep looping	continue
Loop until a condition is met (unknown iterations)	while True + break
Skip invalid data but process everything else	continue

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Debugging Tip: Add Print Statements

When your loop isn't behaving as expected, add a print at the top to see every iteration:

for i, item in enumerate(items):
    print(f"DEBUG: iteration {i}, item = {item}")
    # ... rest of your code

This helps you see if break is triggering too early or continue is skipping the wrong items.

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Challenge Yourself

Once you're comfortable with break and continue, try solving problems without them — using just loop conditions and if/else. Sometimes that's cleaner! The best programmers know when to use each approach.