Python Loop Control Statements (break, continue, pass)

Python Loop Control Statements (break, continue, pass)

These statements modify the behavior of loops.

break: Terminates the loop entirely. continue: Skips the current iteration and moves to the next one. pass: Does nothing, often used as a placeholder.

break

Exits the loop prematurely.

for item in sequence:
    if some_condition:
        break  # exit the loop

continue

Skips the current iteration and proceeds to the next iteration of the loop.

for item in sequence:
    if some_condition:
        continue  # skip the rest of the code in this iteration
    # code to execute if some_condition is False

pass

A null statement, used as a placeholder.

if condition:
    pass  # do nothing

• Video: How to Effectively Use Break and Continue Statements
• Video: Using Python break statement with a while loop

Example #: Using Break Statement in a Loop with Range

for x in range(3):
    if x == 1:
        break

Example 1: Exit a loop when a number is found

# Search for the number 5 and exit the loop when found
numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]

for num in numbers:
    print(f"Checking {num}...")
    if num == 5:
        print("Number 5 found! Exiting the loop.")
        break  # Exit the loop

Output:

Checking 1...
Checking 2...
Checking 3...
Checking 4...
Checking 5...
Number 5 found! Exiting the loop.

Example 2: Password validation with while loop

# Keep asking for a password until the correct one is entered
correct_password = "python123"

while True:
    user_input = input("Enter the password: ")
    if user_input == correct_password:
        print("Access granted!")
        break  # Exit the loop
    else:
        print("Wrong password. Try again!")

Example 1: Skip even numbers using continue Statement

Skips the current iteration and moves to the next loop cycle.

# Print only odd numbers (skip even numbers)
for num in range(1, 11):
    if num % 2 == 0:
        continue  # Skip even numbers
    print(num)

Output:

1
3
5
7
9

Example 2: Temperature Monitoring

Stop monitoring if temperature exceeds a safe limit.

temperatures = [25, 30, 32, 28, 45, 29, 33]  # Sensor readings

for temp in temperatures:
    if temp > 40:
        print(f"ALERT: Temperature {temp}°C is unsafe! Shutting down.")
        break  # Exit immediately
    print(f"Temperature {temp}°C is safe.")

Output:

Temperature 25°C is safe.
Temperature 30°C is safe.
Temperature 32°C is safe.
Temperature 28°C is safe.
ALERT: Temperature 45°C is unsafe! Shutting down.

Example 1: Data Cleaning using continue Statement

Skip invalid entries when processing a dataset.

user_ages = [20, 15, "unknown", 30, -5, 25]  # Some invalid data

print("Valid ages:")
for age in user_ages:
    if not isinstance(age, int) or age < 0 or age > 120:
        continue  # Skip invalid entries
    print(f"- {age} years old")

Output:

Valid ages:
- 20 years old
- 15 years old
- 30 years old
- 25 years old

Task: Coffee Machine Stock Check using break Statement

Simulate a coffee machine that stops serving when a drink is out of stock.

• Input List: ["latte", "cappuccino", "espresso", "mocha", "out_of_stock", "latte"]
• Goal: Loop through the list and stop when “out_of_stock” is found.
• Example Output:

  Serving latte...  
  Serving cappuccino...  
  Serving espresso...  
  Serving mocha...  
  Out of stock! Machine stopping.  
  

Task: Skip Negative Numbers
Calculate the sum of positive numbers in a list, ignoring negatives.

• Input: [5, -2, 10, -8, 3]
• Goal: Use continue to skip negative values.
• Output: Sum of positive numbers: 18

Task: Simple Calculator with Exit using continue and break
Create a loop that:

• Lets users type numbers to add.
• Skips non-numeric inputs (use continue).
• Exits when the user types “quit” (use break).
• Example Output:

  Enter a number (or 'quit'): 5  
  Enter a number (or 'quit'): ten  
  Invalid input!  
  Enter a number (or 'quit'): 3  
  Enter a number (or 'quit'): quit  
  Total: 8  
  

1. Task: Movie Ticket Checker
   Loop through a list of ages and:
   • Skip ages < 0 (invalid).
   • Stop if a “VIP” (age 100+) is found.
   • Input: [25, -5, 30, 105, 40]
   • Output:

      Valid age: 25  
      Skipped invalid age.  
      Valid age: 30  
      VIP detected! Stopping sales.  
     

2. Task: Flight Booking System
   Check seat availability in a list. Stop when a seat is found, or skip “reserved” seats.
   • Input: ["reserved", "reserved", "available", "reserved"]
   • Output:

     Seat 1: Reserved.  
     Seat 2: Reserved.  
     Seat 3: Available! Booked successfully.