Python pass and return

In Python, what is the difference between pass and return

We use pass statement to write empty loops. For example, and are mostly used inside and statements and inside loops and loops.

In Python, what is the difference between pass and return

I have seen some code in Pinax and other django apps that instead of pass, an empty return statement is used. What is the difference and would it have any effect on, for example, the django code below that I am running? The code is a signal method that automatically saves the hashtags into taggit Tag objects for a tweet object .

I saw a question here about whether having or not having a return statement in PHP makes a difference in the interpreted bytecode, but I am not sure if it is relevant to Python.

import re TAG_REGEX = re.compile(r'#(?P\w+)') def get_tagged(sender, instance, **kwargs): """ Automatically add tags to a tweet object. """ if not instance: return # will pass be better or worse here? post = instance tags_list = [smart_unicode(t).lower() for t in list(set(TAG_REGEX.findall(post.content)))] if tags_list: post.tags.add(*tags_list) post.save() else: return # will a pass be better or worse here? post_save.connect(get_tagged, sender=Tweet) 

if not instance: return # will pass be better or worse here? 

Worse. It changes the logic. pass actually means: Do nothing. If you would replace return with pass here, the control flow would continue, changing the semantic of the code.

The purpose for pass is to create empty blocks, which is not possible otherwise with Python’s indentation scheme. For example, an empty function in C looks like this:

In Python, this would be a syntax error:

This is where pass comes handy:

This illustrates some earlier answers.

def p(): "Executes both blocks." if True: print(1) pass if True: print(2) pass def r(): "Executes only the first block." if True: print(1) return if True: print(2) return 

Return exits the current function or method. Pass is a null operation and allows execution to continue at the next statement.

if not instance: return # will pass be better or worse here? 

a pass would continue the execution of the method. A return would terminate the execution of the method. Regarding the following lines, you want to put return here.

else: return # will a pass be better or worse here? 

here it wouldn’t make a difference. Even removing the whole two lines wouldn’t change anything.

But anyway, imagine you would elaborate the method further. It’s better to choose the right flow from the beginning.

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Difference between continue and pass statements in Python

Using loops in Python automates and repeats the tasks in an efficient manner. But sometimes, there may arise a condition where you want to exit the loop completely, skip an iteration or ignore that condition. These can be done by loop control statements . loop control statements change execution from its normal sequence. When execution leaves a scope, all automatic objects that were created in that scope are destroyed. Python supports the following control statement s.

In this article, the main focus will be on the difference between continue and pass statement.

Continue statement

This statement is used to skip over the execution part of the loop on a certain condition. After that, it transfers the control to the beginning of the loop. Basically, it skips its following statements and continues with the next iteration of the loop.

Pass statement

As the name suggests pass statement simply does nothing. We use pass statement to write empty loops. Pass is also used for empty control statements, functions and classes.

Difference between continue and pass

Consider the below example for better understanding the Difference between continue and pass statement.

g e e Pass executed k sg e e Continue executed s

In the above example, when the value of i becomes equal to ‘ k ‘, the pass statement did nothing and hence the letter ‘ k ‘ is also printed. Whereas in the case of Continue statement , the continue statement transfers the control to the beginning of the loop, hence the letter k is not printed.

Loops and Control Statements (continue, break and, Continue Statement It returns the control to the beginning of the loop. break, continue and pass in Python. 22, Nov 19. Difference between continue …

Is there a difference between `continue` and `pass` in a for loop in python?

Is there any significant difference between the two python keywords continue and pass like in the examples

for element in some_list: if not element: pass 

for element in some_list: if not element: continue 

Yes, they do completely different things. pass simply does nothing, while continue goes on with the next loop iteration . In your example, the difference would become apparent if you added another statement after the if : After executing pass , this further statement would be executed. After continue , it wouldn’t.

>>> a = [0, 1, 2] >>> for element in a: . if not element: . pass . print(element) . 0 1 2 >>> for element in a: . if not element: . continue . print(element) . 1 2 

Yes, there is a difference. continue forces the loop to start at the next iteration while pass means «there is no code to execute here» and will continue through the remainder of the loop body.

Run these and see the difference:

for element in some_list: if not element: pass print(1) # will print after pass for element in some_list: if not element: continue print(1) # will not print after continue 

continue will jump back to the top of the loop. pass will continue processing.

if pass is at the end for the loop, the difference is negligible as the flow would just back to the top of the loop anyway.

So why pass in python?

If you want to create a empty class, method or block.

class MyException(Exception): pass try: 1/0 except: pass 

without ‘pass’ in the above examples will throw IndentationError.

Python return statement, A return statement is used to end the execution of the function call and “returns” the result (value of the expression following the return keyword) to …

Difference Between Pass and Continue Keywords in Python

Python has some reserved words known as keywords that the Python interpreter recognizes.

None , return , for , try , while , break , pass , and continue are some of the keywords found in the Python programming language. Interestingly, some keywords are primarily used in standard settings, so their purpose is mistaken.

For example, break and continue are mostly used inside if and else statements and inside for loops and while loops. return is used inside functions, and sometimes, we can also find the pass keyword.

One such pair of keywords is pass and continue . They are found inside loops and conditional statements . Their behavior is sometimes mistaken to be the same.

This article will discuss the difference between pass and continue keywords in Python.

Difference Between pass and continue Keywords in Python

The pass keyword in Python is a null statement. When a Python interpreter lands on this statement, it parses it, but nothing happens.

Generally, developers and programmers use it as a placeholder for code they plan to write in the near future.

Many people think that the pass statement is ignored by a Python interpreter, like comments (statements starting with an # ), but that is not true. A Python interpreter knows that no operation must be performed for the pass statement.

The continue keyword or statement stops the execution of the following code for an iteration. Any code that follows the continue statement does not get executed. A Python interpreter jumps to the next iteration.

The continue statement is used when a programmer or a developer wishes to perform no action for a blocklisted condition.

Let us understand these two statements with the help of some examples. Refer to the following Python code for the pass statement.

for i in range(10): if i % 2 == 0: pass print(i) 

From the output, we can understand that the iteration number will get printed even after the pass statement is present inside the if statement. As mentioned above, a Python interpreter will perform no action when it encounters a pass statement.

Refer to the following Python code for the continue statement.

for i in range(10): if i % 2 == 0: continue print(i) 

From the output, we can infer that the code after the continue statement, no matter if it is inside the same conditional statement block or not, will strictly not get executed. A Python interpreter will shift to the next iteration after discovering the continue statement.

Python Pass

Python Continue Statement, Difference between continue and pass statements in Python. 22, Nov 19. Loops and Control Statements (continue, break and pass) in Python.

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Python Pass Statement

When a python pass statement is executed, basically what happens is nothing. This statement is simply used to execute a block of code in proper syntax without any commands. So pass statement in python is basically null. The result is also null with no output or operational values inside it. It can also be used as a placeholder in the program. In the code, a comment can be ignored but a pass statement cannot be ignored.

For example, as a user I want to execute a code but not at that point of time. May be in future I would want to execute that particular code. Since, it cannot have an empty body, so in that case the compiler might give an error or throw an exception. There comes the use of ‘pass’ when a body is constructed without any use and it contains nothing.

Below is a very simple illustration of a python program which shows the use of ‘pass’:

for letter in 'DeveloperHelps': if letter == 'h': pass print 'This is a pass block' print ('Current Letter is =', letter) print "Thankyou!" 

The output of this python program will be:

Current Letter is = D Current Letter is = e Current Letter is = v Current Letter is = e Current Letter is = l Current Letter is = o Current Letter is = p Current Letter is = e Current Letter is = r Current Letter is = H Current Letter is = e Current Letter is = l Current Letter is = p Current Letter is = s Thankyou! 

There can be other cases as well. Suppose we have a list and the user wants to delete all the odd numbers from that list. For this, the user has to make the use of loop to traverse all the numbers and sort the odd numbers from that list. The logic behind this will be: if the number will be divisible by two, it is even; otherwise it will be removed being odd. Hence, the list will return only even numbers which are divisible by two as the output. In that case, if there is a use of temporary list for the numbers, python won’t support it. The user needs to use ‘pass’ to execute no-operation statement. Or it will simply by pass the code which is not being used.

Below is python code to see what happens if an empty code is run without pass statement:

def Help(): # TODO - implement later

This will throw an error saying “IndentationError: expected an indented block” as the output.

Can we have multiple pass Statement in the same program?

Yes, a python program can have multiple pass statements in a block. The reason lying behind this is a pass statement never terminates the function call. Its only role is to provide an empty block which can be of use in the future.

Python Pass Statement Example

def DeveloperHelps(): pass print('Hello') pass if True: pass pass print('True') else: print('False') pass pass 

The output of the above python program will be:

Python pass Vs continue

When the user uses ‘continue’ keyword, it means he wishes to start the execution of the loop inside the code in the next iteration. However, the use of pass is for an empty block. There is no compulsion for the block to execute. ‘continue’ always goes back to the top of the loop however ‘pass’ keeps moving on with the code flow during the processing.

Python pass vs return

A return statement in python will simply let the user exit the function in operation and return the output. For example, if the user wants to calculate the sum of two numbers. He can simple write return a+b and get the output. However, as we have learnt about pass keyword, it would not return any output. it is carried along in the code for syntactic results majorly.

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