Python break, continue and pass (With examples)

Prerequisites

1. for loops in Python
2. while loops in Python

Loops allow you to perform repetitive tasks on iterables in an automated fashion. However, you might have additional requirements in your loop. For e.g.

1. Stop an iteration when a condition is satisfied
2. Move on to the next iteration without performing any task
3. Add an empty statement placeholder to allow further improvements to your code later.

Keywords like break, continue and pass prove useful in such situations.

break - jumps out of the closest enclosing loop

continue - moves on to the next iteration in the loop

pass - Empty placeholder. Does nothing at all.

break

break is used to exit the loop when a specific condition is met.

Example 1

Code

i = 1
while True:
    print(f"The value of i is {i}")
    # Break the loop when i reaches 10
    if i == 10:
        break
    i+=1

Output

The value of i is 1
The value of i is 2
The value of i is 3
The value of i is 4
The value of i is 5
The value of i is 6
The value of i is 7
The value of i is 8
The value of i is 9
The value of i is 10

The other way to do it would be to include this condition with the while statement.

Code

i = 1
while i <= 10:
    print(f"The value of i is {i}")
    i+=1

Output

The value of i is 1
The value of i is 2
The value of i is 3
The value of i is 4
The value of i is 5
The value of i is 6
The value of i is 7
The value of i is 8
The value of i is 9
The value of i is 10

Now don’t think the usage of break is useless because you can rewrite the above code even smaller without the use of break. In programming, you will be faced with other complicated situations where break will provide you with a cleaner and more efficient code.

Example 2

Let’s try to redo the example from the article on while loops. In that example, a temporary variable user_will_input is used to check if the user wants to enter a friend’s name. If the user enters q, the variable is set to False and the loop is terminated. This time, let’s make use of the break statement when the same condition is met but without using a temporary variable.

Code

friends = []
while True:
    friend_name = input("Enter your friend's name ==> ")
    if friend_name == 'q':
        break
    else:
        friends.append(friend_name)

if len(friends) > 0:
    print(f"Your friends are {','. join(friends)}")
else:
    print("You have no friends!")

Output

Enter your friend's name ==> Shishir
Enter your friend's name ==> Ashish
Enter your friend's name ==> Chinmayee
Enter your friend's name ==> q
Your friends are Shishir,Ashish,Chinmayee

There are 2 observations that you should make.

1. Using break instead of an additional variable achieves the same objective. This makes your code relatively more efficient.
2. In the previous example, the print statement that tells your friends was within an else block. But in this code, the print statements are being used outside the while loop.

The code within an else block(part of the while loop) is only executed when the loop terminates naturally, i.e., you didn’t terminate the loop with break statement. Try and run the below code.

Code

friends = []
while True:
    friend_name = input("Enter your friend's name ==> ")
    if friend_name == 'q':
        break
    else:
        friends.append(friend_name)
else:
    if len(friends) > 0:
        print(f"Your friends are {','.join(friends)}")
    else:
        print("You have no friends!")

Output

Enter your friend's name ==> Shishir
Enter your friend's name ==> Ashish
Enter your friend's name ==> Chinmayee
Enter your friend's name ==> q

As you can see, the code within the else block isn’t executed as your while loop has a break statement in it.

Example 3 - Using break with for loops

You can also use break statements with for loops.

Code - Finding Nemo Example - Start at 2:12

my_list = ["Gill", "Nemo", "Bloat", "Dory", "Gurgle"]

for elem in my_list:
    if elem == "Nemo":
        print("I found Nemo!")
        break
    else:
        print("Still looking for Nemo!")

Output

Still looking for Nemo!
I found Nemo!

Without the use of break statement, you would unnecessarily iterate over every fish in the list. This is very inefficient. By using the break statement, you terminate the iteration, once Nemo is found!

continue

The continue causes an immediate jump to the next iteration in the loop. You can use it to skip code executions for certain conditions.

Example 1

The code below runs infinitely, asking users to input a number and only prints out if the number is odd.

Code

while True:
    number = int(input("Enter a number ==> "))
    if number %2 == 0:
        continue
    print(f"{number} is odd")

Output

Enter a number ==> 3
3 is odd
Enter a number ==> 2
Enter a number ==> 1
1 is odd
Enter a number ==> 10

Because continue immediately moves to the top of the loop, you don’t need to nest the print statement within an else block. The print statement is only reached, if continue statement isn’t executed.

Example 2 - Using continue with for loops

You can also use continue statements in for loops. Let’s go back to the Finding Nemo Example.

Code - Without using continue

my_list = ["Gill", "Nemo", "Bloat", "Dory", "Gurgle"]

for elem in my_list:
    if elem == "Nemo":
        print("I found Nemo!")
        break
    else:
        print("Still looking for Nemo!")

Output

Still looking for Nemo!
I found Nemo!

What we would like to additionally do is, stop printing Still looking for Nemo! when Nemo isn’t found. Also, we want to keep track of the number of fish we had to iterate over until we found Nemo.

Code

my_list = ["Gill", "Nemo", "Bloat", "Dory", "Gurgle"]
number_of_loops = 0
for elem in my_list:
    if elem == "Nemo":
        number_of_loops += 1
        print(f"Fish no. {number_of_loops} is Nemo")
        break
    else:
        number_of_loops += 1
        continue

Output

Fish no. 2 is Nemo

pass

pass is merely a placeholder statement. It does nothing.

Ideally, when you are working on a problem and want to revisit your code later to make changes, you make use of a pass statement.

If you are a beginner, that is the only use of pass statements. However, if you have a little bit of experience with programming, you can use pass statements to ignore exceptions caught during exception handling and to define empty class objects and functions.

Example 1 - Infinite while loop

Code

while True:
    pass

The above code does nothing other than warm up your computer.

Example 2 - Empty functions and classes

Code

def my_new_function():
    pass # Code to be added later

Fun fact - You can also use ... to replace pass statements and your code won’t run into any issue.

Code

def my_new_function():
    ...

The three dots (...) are known as Ellipsis. They do nothing by themselves and hence, can be used to serve as an alternative to the pass statement, especially for code to be filled in later.

Problems

1. Place a break statement in the for loop so that it prints from 0 to 7 only (including 7).

   for i in range(100):
     print(i)
   

2. Write a Python program that prints all the numbers from 0 to 10 except multiples of 3 (use continue).
3. Write a Python program to construct the following pattern.

   * 
   * * 
   * * * 
   * * * * 
   * * * * * 
   * * * * 
   * * * 
   * * 
   *