How to write an empty function in Python - pass statement

During the development of a Python program, we might want to create a function without implementing its behavior. In such cases, we can define the function and use the pass statement inside it to avoid syntax errors.

To write empty functions in Python, we use pass statement. pass is a special statement that does nothing. It only works as a dummy statement.

Empty Function with pass

def fun():
    pass  # Function logic to be added later
# Calling the empty function
fun()  # This does nothing for now

In this example, the function fun doesn’t perform any action because of the pass statement. However, it’s still defined and can be invoked like any other function.

Example with while Loop

A while loop repeatedly executes a block of code as long as the condition is true. If you want to create a while loop structure without implementing the logic right away, you can use the pass statement.

i = 0
while i < 10:
    pass  # Placeholder for future code
    i += 1

In this example, the while loop runs as long as i is less than 10. The pass statement indicates that the loop does nothing for now, but the loop still increments i.

Example with for Loop

A for loop iterates over a sequence of elements. You can use the pass statement to define a for loop without any operation for each iteration.

for i in range(5):
    pass  # Placeholder for future code

Here, the for loop iterates over the range from 0 to 4, but it doesn’t perform any action because of the pass statement.

Example with if-else Statement

The if-else statement executes a block of code based on a condition. You can use the pass statement in both the if and else blocks to indicate that these blocks are empty.

x = 10
if x > 5:
    pass  # Placeholder for future code
else:
    pass  # Placeholder for future code

In this example, the if condition checks if x is greater than 5. Both the if and else blocks contain the pass statement, indicating that no action is taken regardless of the condition.

Benefits of Using pass in Functions

• Helps Maintain Code Structure: We can set up the skeleton of your program early on without having to worry about implementing every detail at once.
• Keeps Syntax Valid: It prevents syntax errors when defining functions that have no body yet. Without pass, Python would raise an indentation error if the function body is left empty.
• Facilitates Incremental Development: We can focus on high-level logic first and implement specific functionality in small steps.
• Improves Readability and Collaboration: When working in teams, using pass clearly signals that a function is yet to be implemented, making the code easier to read and understand.