In Python, what is the difference between Yield and Return?

In Python, the definition ofgeneratoris done with the help ofyieldstatement. So before we get into the details of whatyieldis actually used for, it's important to understand an overview ofgenerators. If you're new to Python, there's a good chance you've used a Python generator before. Generators play an important role in Python. In Python, iterators can be generated using generators, but the process takes a slightly different form.

Python generators are functions that can be paused and resumed dynamically and create a sequence of results. They can also be used to generate random numbers. In Python 2.2, generators were first introduced as an optional feature. In Python 2.3, they are enforced. Generator functionality has been greatly improved in Python 2.5, although they already have sufficient functionality.

To maintain backward compatibility, the addition of generators in Python 2.2 resulted in the introduction of a new keywordcalled"yield". In order to use generators, we need to import them from the_future_module. When generators became the default in the Python 2.3 release, this was changed to reflect the fact that the change was no longer needed.

Use theyieldstatement to temporarily stop the execution of a function, which then returns a value to the caller while saving the function's state for later restoration. This means that the entire generator can still be restarted after getting the return value. Execution of a function terminates with a return statement, which also returns a value to the person who called the function. If missing, your function will return nothing.

What is Python Yield?

In Python generators, theyieldstatement replaces the function'sreturnso that a value is returned to the person who called the generator without deleting any local variables. In order to better understand the function ofyieldstatement execution in Python programming, you first need to be familiar withgenerators.

The difference between a generator function and an ordinary function is that there is a "yield" statement in the definition of the generator function. It begins with the "yield" keyword, which identifies the generator object to be returned to whoever calls this function.

In Python, a specific type of function called a "generator" returns not a data value to the person who called the function, but another generator object. With theyieldkeyword, you can temporarily stop the execution of a function, save the state, and resume the function later.

Example

Look at the example below -

# Use of yield def printresult(String): for i in String: if i == "p": yield i # Initializing string String = "Happy Birthday" ans = 0 print ("The number of 'p' in word is: ", end = "" ) String = String.strip() for j in printresult(String): ans = ans + 1 print (ans)

Output

The number of 'p' in word is: 2

What is Python Return?

In contrast to theyieldstatement, thereturnstatement causes the function to terminate while passing the value back to the function that called it. Functions that are more procedural in nature do not return anything explicitly to the caller, but instead return a value that is sent back to the calling function. Although a function can have multiple return statements, only one of them can be called for each call to each of those statements.

Almost always place thereturnstatement at the very end of a function block, its purpose is to return the final result of executing all statements contained in the function. However, areturnstatement may also appear before a function block to stop execution of all subsequent statements in the block. This can occur if it is used to prevent the execution of a function. This causes the caller to immediately restart the execution of the program. The "None" return object type is equivalent to that in Python when no value is provided for thereturnobject.

Example

The following example shows the use ofreturnin Python -

# Show return statement class Test: def __init__(self): self.str = "Happy Birthday" self.x = "Pradeep" # This function returns an object of Test def fun(): return Test() # Driver code to test above method t = fun() print(t.str) print(t.x)

Output

Happy Birthday Pradeep

Difference between Yield and Return in Python

The following table highlights the main differences between Yield and Return in Python -

The code written after the

Basic comparison	Yield	return
Base	In most cases, you will need to use the yield function to convert a typical Python function into a generator.	In most cases, the end of execution is signaled by using the return keyword, which "returns" the result to the statement that called it.
Function	It replaces the function's return in order to pause the execution of the function without losing any local variables.	It exits the function and returns a value to its caller.
use	The caller will use this function when the generator provides intermediate results to the caller.	When a function is preparing to pass a value, it is necessary to use this.
implement	yield statement will be executed in the following function call.	Although the code written after the return statement will not be executed.
Compile	It has the ability to run multiple times.	It only runs once at a time.

in conclusion

The

yieldstatement generates a generator object and can return multiple values to the caller without terminating the program, while thereturnstatement is used to return a value from inside the function, it terminates the program. The return statement is used to return a value from within a function to the caller.

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