What Does Function Mean In Javascript

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A python function is a group of code. To run the code in a function, you must call the function. A function can be called from anywhere after the function has been defined. Functions can return a value using a return statement.

Functions are a common feature of all programming languages. They allow developers to write blocks of code that perform specific tasks. A function can run as many times as a developer wants in their code.

Functions allow developers to reduce repetition in code because they can run the same block of code multiple times in a program.

This tutorial will discuss, with examples, the basics of Python functions, how to create and call a function, and how to work with arguments. By the end of reading this tutorial, you will be an expert at writing functions in Python.

What is a Python function?

A function is a block of code that is executed only when it is called. Python functions return a value using a return statement, if specified. A function can be called nowhere after the function has been declared.

By itself, a function does nothing. But, when you need to use a function, you can call it and the code for the function will be executed.

In Python, there are two types of functions:. User defined and integrated. Built-in functions are functions such as:

  • print (), which prints a statement to the console
  • Python len () , which calculates the length of a list
  • Python str () , which converts a value in a string

User- defined functions are reusable blocks of code written by you, the developer. These code blocks allow you to organize your code more efficiently. This is important because the more organized your code is, the easier it will be to maintain

How to define a Python function

Define a function way creating the function . This involves writing a block of code that we can call by referring to the name of our function. A function is indicated by the keyword def, followed by a function name and a series of parentheses

For this example, we’ll create a simple function that prints the declaration It & rsquo ;. Monday at the console. To do this we can use this code:

When we run our code, nothing happens. This is because in order for our function to run, we have to call it. To do this, we can refer to our function name like this:

Our code returns:

break down the main components of our function:

  • the keyword def is used to indicate that we want to create a function.
  • print_monday is the name of our function. It should be unique.
  • () is where our parameters will be stored. We ’ ll talk about this later
  • : .. marks the end of our function header

Now our functions can be as complex as we want them to be. Suppose we want to write a program that tells a user how many letters there are is on their behalf. We could do that using this code:

If we run our code and type the name "Elizabeth", the following response is returned:

we define a function called calculate_name_length () . In the body of the function, we ask the user for their name and then use len () to calculate the length of the user’s name. Finally, we print "The length of your name is [length] letters. "When the duration is the length of the user name, on the console

Parameters and arguments of functions

In our first examples, we used empty parentheses with our functions. this means that our functions do not accept any arguments.

arguments allow you to pass information into a function that the function can read. the arguments of a function are indicated in parentheses after the name of the function.

Let’s move on to a basic example to illustrate how they work arguments.

Example of Python parameters and arguments

Suppose we want to create a program that multiplies two numbers we could do it using this code:.

Our program returns Python:

First , we’ll define a function called multiply_numbers . The names of the parameters in the function accepted by our code are: number1 and number2. We define them in parentheses, which is where the parameter list is defined.

Next, we declare a Python variables called "answer" which multiplies the values ‚Äã‚Äãof number1 and number2. Then we print an instruction to the console with the entire math sum written, followed by the answer to the math problem.

We have specified the required arguments. Indeed, we did not set the default values ‚Äã‚Äãfor each argument. It is necessary to specify a certain number of arguments equal to those of the list of parameters otherwise the Python interpreter returns an error.

Towards the end of our program, we call multiply_numbers function twice.

First , we specify arguments 5 and 10. Our program multiplies these values ‚Äã‚Äãto calculate 50. Next, our program prints "5 x 10 = 50" to the console. Then we specify arguments 15 and 2, which our program multiplies. Then our program prints "15 x 2 = 30" to the console

By default, the order of the arguments passed in function is the order in which they are processed by the program. When we run "multiply_numbers (5, 10)", the value of "number1" becomes 5. The value of "number2" becomes 10. We will talk about how to replace it in the " Keyword Arguments " section.

For more information on arguments see our Python optional arguments tutorial

A note:. Parameters and Arguments

The terms parameter and argument refer to the same thing: passing information to a function. But there is a subtle difference between the two

a parameter is the variable inside the parenthesis in a function. An argument is the value passed to a function when it is called. So, in our last example, "number1" and "number2" are parameters and 5 and 10 are arguments.

keyword arguments Function

As we have, the order you pass the arguments in is the order in which your program will process them. Then the first parameter will be assigned to the first argument and so on . However, there is a way to bypass this rule.

You can use keyword arguments in a function call, which allows you to assign the value of an argument based on the name of the parameter. Using keyword arguments lets you specify the keyword value in the order you want.

words - key arguments work because you are going to use words - key to match the parameter values, rather than relying on the order of arguments to transmit values.

Suppose you create a program that prints the name and email address of someone who has joined a mailing list. We could write this program using the following code:

Our feedback from code:

We declare a function that accepts two parameters: name and email. We print "Name:" on the console, followed by the value in the name parameter. Then , we print "_EMAIL:" _ to the console, followed by the value in the email parameter. We use the instructions of print () Python to print these values to the console.

Then call our function and specify two arguments. email The argument is made equal to [email protected] Com and name argument is made equal to Alex Hammond .

In our code, we separate the name of the argument and its value in the way of a sign of equality (=). This meant that we no longer had to specify our arguments in the order our parameters appear (name, email). We could use any order we want.

Default Argument Values

Additionally, you can specify a default argument value for a parameter in a function.

suppose we want the value of email [email protected] by default. We could achieve this using the following code:

Our code returns Python:

We set the value by default parameter email must be [email protected] < / a>. When we run our code and call the print_info () function, we don’t need to specify a value for the email argument. In this example, when we run print_info (), we specify only one argument:. Username

Return Values to Main Program

So far we have discussed how to pass values ‚Äã‚Äãinto a function. But a function can also be used to pass values ‚Äã‚Äã the rest of a program

the return statement closes a function and returns a value to the main program. If you use the return statement with no arguments, the function will return the value None.

Suppose we want to create a program that multiplies two numbers, so when those two numbers have been multiplied, we want to return them to our main program. the make using this code:

Our code returns:

First , we define a function called multiply_numbers. That this function accepts two parameters: number1 and number2 . When this function is called, the values ‚Äã‚Äãof "number1" and "number2" are multiplied. Then we use the return declaration to pass the multiplied number to the main program

We call the multiply_numbers () function and specify two arguments .:5 and 6. Note that we also assign the result of the function to the variable "ans". When this line of code is executed, our function is called and the result is assigned to "ans". So our code prints the value of "ans", which in this case is 30.

Python return Execution of Abandons a function, even if it does not return value. Here is an example of this behavior in action:

Our code does not print anything on the console. Although there is an "impression (" Done ")" statement in our code, it is not executed.

Indeed, when our loop is executed four times (when i is equal to 4), the return instruction is executed. This causes our function to stop executing and prevent our execution loop.

After our function stops working, the code in our main program will continue to run.

Conclusion

Python functions are blocks of code that perform a certain action. Functions can be called as many times as desired in a program. This means that you can run the same block of code multiple times without having to repeat the code.

The functions allow you to reduce repetition in your code, thus making your programs easier for you and for both to read. of other programmers.

For a challenge, write a function that prints each number between 1 and 10 (including 10) on the console. This function must contain a loop. When the function is complete, you should print "Done!" " To the console. Call your function once at the end of your program

The output should be:.

This tutorial has reviewed the basics of python functions, how to write and call a function, and how to work with arguments and parameters. You are now ready to start writing functions in Python like an expert

For recommendations on the best Python courses, books, and learning resources , check out our comprehensive Python Learning Guide .

👻 Read also: what is the best laptop for engineering students?

We hope this article has helped you to resolve the problem. Apart from What Does Function Mean In Javascript, check other __main__ Python module-related topics.

Want to excel in Python? See our review of the best Python online courses 2023. If you are interested in Data Science, check also how to learn programming in R.

By the way, this material is also available in other languages:



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Ken Lehnman

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