What Does Function Mean In Javascript

Michael Zippo 04.11.2021

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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