Loop Control: break, continue, pass and else

break

break exits the loop immediately. Nothing else in the body runs, and the loop does not continue.

names = ["Meera", "Arun", "Sara", "Ravi"]

for name in names:
    print("checking", name)
    if name == "Sara":
        print("found")
        break

print("finished")

checking Meera
checking Arun
checking Sara
found
finished

break only leaves one loop

for row in range(3):
    for column in range(3):
        if column == 1:
            break               # leaves the INNER loop only
        print(row, column)

0 0
1 0
2 0

To leave both loops, use a flag, the loop else, or - most cleanly - put the loops in a function and return.

def find_in_grid(grid, target):
    for r, row in enumerate(grid):
        for c, value in enumerate(row):
            if value == target:
                return r, c        # leaves both loops at once
    return None


print(find_in_grid([[1, 2], [3, 4]], 3))     # (1, 0)

continue

continue skips the rest of the current iteration and starts the next one.

for n in range(1, 11):
    if n % 2 == 0:
        continue          # skip even numbers
    print(n, end=" ")     # 1 3 5 7 9
print()

lines = ["# a comment", "", "host = localhost", "  ", "port = 8080"]

for line in lines:
    line = line.strip()
    if not line:
        continue                 # skip blank lines
    if line.startswith("#"):
        continue                 # skip comments
    print("setting:", line)

This filtering shape - skip everything uninteresting first, then handle the real case at the bottom with no indentation - is one of the best uses of continue.

continue in a while loop needs care

i = 0
while i < 5:
    if i == 2:
        continue        # INFINITE LOOP: i is never incremented
    print(i)
    i += 1

i = 0
while i < 5:
    i += 1              # advance FIRST
    if i == 3:
        continue
    print(i)

In a for loop the iterator advances by itself, so continue is always safe. In a while loop it jumps straight back to the condition, skipping any increment below it.

pass

pass does nothing at all. It exists because Python blocks cannot be empty.

for n in range(5):
    if n == 3:
        pass          # a placeholder: nothing happens, the loop continues
    print(n)          # 0 1 2 3 4 - all of them


def not_implemented_yet():
    pass


class Marker:
    pass


try:
    risky()
except ValueError:
    pass              # deliberately ignore this error

The three are not interchangeable

The loop else clause

Both for and while may have an else. It runs when the loop finishes without hitting break.

names = ["Meera", "Arun"]
target = "Sara"

for name in names:
    if name == target:
        print("found")
        break
else:
    print("not found")        # runs, because no break happened

The keyword is badly chosen. Read else here as "no break", not as "otherwise". It runs after a normal, complete loop.

Where it is genuinely useful

def is_prime(n):
    if n < 2:
        return False
    for divisor in range(2, int(n ** 0.5) + 1):
        if n % divisor == 0:
            return False
    return True


print([n for n in range(2, 30) if is_prime(n)])

required = ["name", "email", "phone"]
record = {"name": "Meera", "email": "m@example.com", "phone": "9000000000"}

for field in required:
    if field not in record:
        print("missing", field)
        break
else:
    print("record is complete")

The alternative is a found = False flag set inside the loop and checked afterwards. The else clause removes the flag entirely. Many teams still prefer the flag because it is more obvious to a reader; both are acceptable, and consistency matters more than the choice.

Combining them

entries = ["12", "abc", "-5", "0", "quit", "99"]

for entry in entries:
    if entry == "quit":
        print("stopping early")
        break
    if not entry.lstrip("-").isdigit():
        print("skipping", entry)
        continue
    value = int(entry)
    if value <= 0:
        continue
    print("accepted", value)
else:
    print("processed every entry")

Common mistakes

• Expecting break to exit nested loops. It exits one level.
• Using continue in a while loop above the increment, causing a hang.
• Confusing pass with continue. pass does not skip anything.
• Reading the loop else as "if the loop did not run".
• Using a bare except: pass, which silently swallows every error including typos.
• Putting break inside an if whose condition can never be true.

Best practices

• Use continue to filter early and keep the main body unindented.
• Extract nested loops into a function and use return instead of flags.
• Use the loop else for search loops, or a clearly named flag - but be consistent.
• Never write except: pass without a comment explaining why the error is safe to ignore.
• Keep the number of exit points in one loop small enough to hold in your head.

Practice

1. Search a list of dictionaries for a matching record, reporting failure, using the loop else and then using a flag. Compare the two.
2. Write a nested loop that stops entirely on the first negative value found in a grid.
3. Explain why continue in a while loop can hang and how to place the increment safely.
4. Filter a list of raw input strings, skipping blanks and comments, and stop at a line reading END.
5. Predict the output of a loop containing all three of break, continue and pass, then check it.

Conclusion

break leaves, continue skips, pass does nothing. The loop else means "no break happened", and when nesting gets awkward the real answer is usually a function with a return.