Python pass Statement – pass in Python

Filed Under: Python

Dear learners, how is everything going? Hope that you’re learning well. In our previous tutorial, we learned about Python break and continue statement to control python loops. You can find that tutorial here. In this tutorial, we are going to learn about Python pass statement.

Python pass statement

You can consider python pass statement as no operation statement. The difference between Python comments and pass statement is; comments are being eliminated while interpreting the program but pass statement does not. It consumes execution cycle like a valid statement. For example, for printing only the odd numbers from a list, our program flow will be:


List <- a list of number
for each number in the list:
	if the number is even,
		then, do nothing
	else 
		print odd number

Now if we convert the above things to python,


#Generate a list of number
numbers = [ 1, 2, 4, 3, 6, 5, 7, 10, 9 ]
#Check for each number that belongs to the list
for number in numbers:
        #check if the number is even
	if number % 2 == 0:
                #if even, then pass ( No operation )
                pass
	else:
                #print the odd numbers
		print (number),

The output will be


>>> 
================== RESTART: /home/imtiaz/Desktop/pass1.py ==================
1 3 5 7 9
>>> 

Suppose you need to implement many function one by one. But you have to check every function after implementing the function. Now if you leave the things like this:


def func1():
        # TODO: implement func1 later
 
def func2():
        # TODO: implement func2 later
        
def func3(a):
        print (a)
 
func3("Hello")
 

Then, you will get IndentationError for this.
python output showing IndentationError, python pass statement

So, what you need to do is, add pass statement to each no-implemented function like this.


def func1():
        pass # TODO: implement func1 later
 
def func2():
        pass # TODO: implement func2 later
        
def func3(a):
        print (a)
 
func3("Hello")

For the above code, you will get output like this


================== RESTART: /home/imtiaz/Desktop/pass3.py ==================
Hello
>>> 

Why should we use Python pass Statement

Now, a question may come to your mind, why should we use Python pass statement? Actually it seems that, in our previous example, if we just comment-out the unimplemented functions, like below, we will still get our desired output.


#def func1():
        # TODO: implement func1 later
 
#def func2():
        # TODO: implement func2 later
        
def func3(a):
        print (a)
 
func3("Hello")

But if you work with a huge python project, at one time, you may need something like pass statement. That’s why pass statement is introduced in Python.

That’s all for today. Hope that, you learned well about Python pass statement. Stay tuned for our next tutorial and for any confusion, feel free to use the comment box.

Reference: Official Documentation

Comments

  1. Pankaj Singh says:

    Ya ……I understood but little bit confused about its real implementation

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