How does return work in python

This is the point where functions can and should be used in Python. We could use wildcards in the code instead of names. In the following diagram we use a piece of the puzzle. We only write the code once and replace the puzzle piece with the corresponding name:. Of course, this was no correct Python code. We show how to do this in Python in the following section. The following code uses a function with the name greet.

The previous puzzle piece is now a parameter with the name "name":. We used a function in the previous code. We saw that a function definition starts with the def keyword. The general syntax looks like this:. The parameter list consists of none or more parameters. Parameters are called arguments, if the function is called. The function body consists of indented statements.

The function body gets executed every time the function is called. We demonstrate this in the following picture:. We call the function twice in the program. The function has two parameters, which are called x and y.

This means that the function f is expecting two values, or I should say "two objects". The mechanism for assigning arguments to parameters is called argument passing.

When we reach the return statement, the object referenced by z will be return, which means that it will be assigned to the variable res1. After leaving the function f , the variable z and the parameters x and y will be deleted automatically.

The next Python code block contains an example of a function without a return statement. We use the pass statement inside of this function. This means that when it is executed, nothing happens. It is useful as a placeholder in situations when a statement is required syntactically, but no code needs to be executed:.

It is used by the help function:. Our next example could be interesting for the calorie-conscious Python learners. We also had an exercise in the chapter Conditional Statements of our Python tutorial. We will create now a function version of the program. The body mass index BMI is a value derived from the mass w and height l of a person.

The BMI is defined as the body mass divided by the square of the body height, and is universally expressed. The following shows code which is directly calculating the bmi and the evaluation of the bmi, but it is not using functions:.

When we define a Python function, we can set a default value to a parameter. If the function is called without the argument, this default value will be assigned to the parameter. This makes a parameter optional. I'll attempt to explain this better with some examples, and a couple definitions from Wikipedia. Here is the definition of a function from Wikipedia A function, in mathematics, associates one quantity, the argument of the function, also known as the input, with another quantity, the value of the function, also known as the output..

Think about that for a second. What does it mean when you say the function has a value? Assuming the two values are the same type of value Why would you want that you ask? What about other functions that may accept the same type of value as an input?

An expression is said to be referentially transparent if it can be replaced with its value without changing the behavior of a program It might be a bit hard to grasp what this means if you're just new to programming, but I think you will get it after some experimentation. Just remember that when you use return you are basically saying "A call to this function is the same as writing the value that gets returned" Python will actually insert a return value for you if you decline to put in your own, it's called "None", and it's a special type that simply means nothing, or null.

Wes Wes 2, 1 1 gold badge 16 16 silver badges 31 31 bronze badges. I think the dictionary is your best reference here Return and Print In short: return gives something back or replies to the caller of the function while print produces text. Kimvais Kimvais I guess from this simple example, you would understand the meaning of return command. Jeffrey Swan 2 2 gold badges 8 8 silver badges 23 23 bronze badges. Output: two digits This code that appears after the conditional statements, or the place the flow of control cannot reach, is the dead code.

Akaisteph7 4, 1 1 gold badge 11 11 silver badges 34 34 bronze badges. Just to add to Nathan Hughes's excellent answer: The return statement can be used as a kind of control flow. Christa 1 1 gold badge 4 4 silver badges 8 8 bronze badges. LondonRob LondonRob 58k 32 32 gold badges silver badges bronze badges. I think a really simple answer might be useful here: return makes the value a variable, often available for use by the caller for example, to be stored by a function that the function using return is within.

Fully admitting that the more thorough answers are more accurate. Andy Andy 1, 1 1 gold badge 17 17 silver badges 28 28 bronze badges.

Expected result: 3 You passed 0 out of 3 test cases. Ashwini Chaudhary k 50 50 gold badges silver badges bronze badges.

Hmm, your print code didn't fail for the test cases you provided. They were all correct! Here is my understanding. What this does is the following: Our function is called with two arguments: a and b. You might say this as, "I add a and b then return them. Then, you should specify by a set of parentheses.

The parenthesis can hold any parameters that you want your function to accept. The Python return keyword exits a function and instructs Python to continue executing the main program. The return keyword can send a value back to the main program. A value could be a string, a tuple, or any other object. Get matched to a bootcamp today. The average bootcamp grad spent less than six months in career transition, from starting a bootcamp to finding their first job.

This is useful because it allows us to process data within a function. Then, we can return the data to our main program, so we can use it outside our function. Data processed within a function is only accessible within the function.

This is only the case unless you use the return statement to send the data elsewhere in the program. The return keyword can appear anywhere within a function, and when the code executes the return statement, the function will be exited. The return statement returns a value to the rest of the program, but it can also be used alone.

If no expression is defined after the return statement, None is returned. You may decide not to specify a value if you only want a function to stop executing after a particular point. This is a less common use case of the Python return statement. Say that we are operating a restaurant. We want to create a program that returns the cost of the sandwich meals we have on the menu. If the return statement is without any expression, then None is returned.

Please note here that the return statement in Python can not be used outside the function. In this example, we have defined a function that returns the sum of two values. This example returns one value. To return multiple values in Python from a function, we can use the following ways. To return multiple values by separated commas, use the return statement. In Python, you can return the multiple values separated by commas.

The returned values are Python tuple with comma-separated values. From the output, you can see that the function has returned a tuple containing command-separated values.