break is used to exit the loop early, and continue is used to skip the current iteration. For example, use break to terminate the loop when looking for a specific value; use continue to skip the current item when filtering invalid data. Both only affect the loops at the level, and additional outer loops need to be processed when nesting. Rational use can improve code clarity, but abuse should be avoided.
When you're working with loops in Python (or most programming languages), there are times when you want to either exit the loop early or skip part of the current iteration. That's where break and continue come in handy.
Using break to Exit a Loop Early
The break statement is used when you want to immediately terminate the loop, no matter how many iterations are left. It's especially useful when you're searching for something and want to stop once you find it.
For example:
- You're looping through a list of user inputs and want to stop when you find a specific value.
- You're reading lines from a file and want to exit once you hit an error or end marker.
for number in range(10):
if number == 5:
break
print(number) In this case, it prints numbers from 0 to 4 and stops because break interrupts the loop when number reaches 5.
You'll often see break used inside while True loops that wait for a certain condition to occur — like waiting for user input or a network response.
How continue Skips Part of a Loop
If you want to skip just the current iteration and move on to the next one, continue is your go-to. It doesn't stop the whole loop — it just jumps back to the top and starts the next round.
A common use case:
- Filtering out unwanted values ??in a list before processing.
- Skipping empty lines or invalid data while parsing files.
for number in range(5):
if number == 2:
Continue continue
print(number)This will print 0, 1, 3, 4 — skipping 2 entirely.
You can think of continue as a shortcut to avoid nesting too much logic inside conditions. Instead of writing:
if number != 2:
do_something()You can write:
if number == 2:
Continue continue
do_something()It keeps your code cleaner, especially when dealing with multiple conditions.
Combining break , continue , and Nested Loops
Sometimes you'll have loops inside other loops — nested loops. In these cases, keep in mind that break and continue only affect the innermost loop they're in unless you add extra logic to control outer loops.
Here's a simple example:
for i in range(3):
for j in range(3):
if j == 1:
Continue continue
print(f"i={i}, j={j}") Only the inner loop is affected by continue . If you need to break out of both loops, you might:
- Use a flag variable
- Refactor into a function with
return - Consider restructuring your logic
Also, be careful not to overuse them — too many break s and continue s can make code harder to follow.
So, break gets you out fast, and continue lets you jump ahead. Both are useful tools, but best used sparingly to keep your loops readable.
The above is the detailed content of How do I use break and continue statements within loops?. For more information, please follow other related articles on the PHP Chinese website!
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