I was a newbie in the programming world when I first started learning Python. My goal with this guide is to help make your life easier by explaining some basic functions that are helpful for beginners, as well as great places to find more information you can use later on.
Python is one of the most popular programming languages. It has a lot of built-in functions that make it easy to start with. This article will show you how to use some of these functions for beginners. Read more in detail here: python functions for beginners.
Python is one of the most widely used programming languages. Python can be used to create almost anything by skilled programmers. You must first grasp Python functions before you can write outstanding Python code. Functions are the first step in writing modular code and reducing repetition.
You’ll learn how to get started with Python functions in this course. You’ll learn what a Python function is, how to create function arguments, how to call them, the scope of a function, and much more!
Let’s get started!
Prerequisites
This is a hands-on instruction with a variety of demonstrations. If you want to follow along, you’ll need the following items:
- Any operating system that supports Python v3+. Python 3.8.4 will be used in this course.
How Do You Install Python 3.6? Related:How Do You Install Python 3.6?
What is the definition of a Python function?
When you first start creating code in almost any programming language, you’ll usually do it in a single file. The code is then executed in one big piece. This strategy may work at first, but it will eventually become unmanageable.
You discover you’re duplicating code when all you actually need is a means to call snippets of code when they’re required. You recognize you need to study functions at this point, and Python is no exception.
A Python function, like other language functions, is a block of code that Python only runs when it is called upon. It’s a reusable chunk of Python code that you may use in other portions of your script as required.
Python functions also have optional inputs and outputs, allowing you to change how they behave.
Making Your First Python Function and Calling It
Now it’s time to get your hands dirty and create your first Python function! To begin, open your preferred code editor and write (and save) the python function demo.py Python script.
1. Copy and paste the following code into the Python script and save it.
The def keyword is used to declare or define a Python function, which is followed by the function name and a pair of parentheses with optional arguments that you’ll learn about later. The function header is the first line of code.
Make careful to name functions according to their function. A function name of someFunction(), for example, might work in the code snippet below, but it doesn’t adequately convey what the function performs.
After you’ve specified the function header, you’ll need to add the function body, which contains the code that the function should run.
For Python to identify that code is part of the function body, be sure to include four spaces of a tab for all code in the function body.
## Create a function named printHelloWorld (def). This is the def printHelloWorld() function header: ## Print Hello World! when printHelloWorld() is invoked! ## This is the body print(“Hello World!”) function.
2. Now it’s time to run the script. It’s worth noting that Python did nothing. It did not print Hello, world! as you would anticipate. In fact, it didn’t seem to have any effect! Why? Because if you don’t call a function first, it won’t run the code in the function body.
3. Finally, add the printHelloWorld() line to your script to make it appear like this, then run it again.
## Create a function named printHelloWorld (def). This is the def printHelloWorld() function header: ## Print Hello World! when printHelloWorld() is invoked! ## This is the body print(“Hello World!”) function. printHelloWorld()
Python now delivers the expected Hello World! text, as seen below. Because you’ve called or executed the printHelloWorld() method in the same script, it accomplishes this.
In a Python terminal, copying and pasting a function declaration and function call and running it
Parameters and Arguments for Python Functions
This function has no inputs in the printHelloWorld() function sample you’re working with. Python runs it when you call it by its name. But what if you need to modify the function’s behavior or produce a different result? This will be accomplished by the use of a parameter.
The terms ‘parameter’ and ‘argument’ are often used interchangeably. The parameter is technically the name (param), and the argument is the value of the parameter that is supplied to the function when it is called.
A parameter is a mechanism to supply information to a function that it may utilize when it is called. Add a parameter named param to the function using the tutorial example by entering it between the parentheses in the function header.
Then, in the print() line, replace World with a placeholder for the param argument, which will be the value of param when the function is called.
Once you’ve finished, run the script below.
## Define (def) a called called printHelloWorld. This is the function header ## This function has a single parameter def printHelloWorld(param): ## When the printHelloWorld() is called, print Hello <whatever the parameter ## argument is>! print(f”Hello {param}!”) printHelloWorld(‘earth’)
The print() line in the example function now utilizes Python string interpolation to define a variable inside a string.
Python function arguments are shown.
Creating a Function with Multiple Parameters
You may add as many as you like by using the same procedure as when adding a single function parameter. Substitute the following script for the example. You may enter as many comma-separated options as you like. You may then refer to the parameter values inside the function body after they’ve been defined.
Rerun the sample script below to see how Python prints the values of each argument you supply to the function.
## Create a function named printHelloWorld (def). This is the function header: def printHelloWorld(param,param2,param3): printHelloWorld(param,param2,param3): printHelloWorld(param,param2,param3): printHelloWorld(param,param2,para ## Print Hello… followed by the values ## of the arguments when printHelloWorld() is invoked. print(f”Hello, parameter, parameter2, parameter 3!”) printHelloWorld(‘earth’,’wind’,’fire’)
In Python functions, parameter order is crucial. Python will match each argument to a parameter in the same order that you specify the parameters in the function header when you send arguments to a function parameter.
Arguments to Default Functions
If you often send the same argument to a function parameter, it would be a good idea to define a default argument for that parameter. If you want the param3 parameter in the sample function to have the value Earth by default, for example, you’d declare the value as follows.
## def printHelloWorld(param,param2,param3=’Earth’) has three arguments with one default argument: print(f”Hello, parameter, parameter2, parameter 3!”) printHelloWorld(‘wind’,’fire’)
If you want to alter the default argument value at any stage, just provide param3’s argument when calling the function, as shown below.
printHelloWorld(‘wind,’fire,’Something else,’Something else,’Something else,’Something else,’Something else,’Something else,’Something else
Changing the default parameter value of a function
Scope of Work
Python, like many other programming languages, contains a notion known as scope. The scope relates to the location of variables and other data. For example, since a Python variable is “local” to where it was declared, Python may identify it when you define it in a script and call it in the same script (not in a function).
## variable = ‘foo’ Because the variable was declared and referenced in the same scope print, this works (variable)
This article will not go into great detail about scope, but it is vital to understand when creating functions.
There are three variables in the instructional example function that reflect the argument value of three parameters: param, param2, and param3. Local variables refer to the three variables inside the function. Because they are specific to the function, they are referred to as ‘local’ variables. As a result, they are limited to the function.
Add the identical print() command just below the line in the sample script that is in the function body to show this notion, then run the script.
print(f”Hello param,param2,param3!”) def printHelloWorld(param,param2,param3=’Earth’) def printHelloWorld(param,param2,param3=’Earth’) def printHelloWorld(param,param2,param3=’Earth’) def printHelloWorld(param,param2,param3=’Earth’) def print(f”Hello param, param2, and param3!”) printHelloWorld(‘wind’,’fire’) print(f”Hello param, param2, and param3!”)
Notice how the function outputs the parameters as anticipated when they are referred inside the code, but fails when they are referenced outside of the function.
Outside of the function’s local scope, Python cannot view the param, param2, or param3 variables. These variables do not exist in the scope of the script.
The parameter is printed by the function.
Using the Python Function Return Statement to Return Output
The function you’ve been dealing with thus far in this lesson has theoretically returned something. You’ve been returning text to the terminal using the print() command. If you need to check the output, the print() statement is ideal.
When your function needs to return other sorts of Python objects, though, you’ll need to utilize the return statement. You must use the return statement if you need to assign a function’s return value to a variable and utilize it elsewhere.
Create a new function named multipleValues() and call it as shown below to showcase the Python function return statement. Given two inputs as parameters, this function multiplies them together.
Definately multiplied Values(param,param2): multiply param * param2 Values(1,4)
When you run this script, you’ll see there’s no output, which may lead you to conclude Python didn’t run the function, but it did. Because you didn’t utilize the return statement, the function didn’t return anything.
When code like 1 * 4 returns a value outside of a function, but the identical code within the function seems to return nothing without a return statement, this is referred to as implicit output.
Now, as seen below, add the Python function return statement, and the function will return the product of 1 and 4.
Definately multiplied return param * param2 multiply values(param,param2) Values(1,4)
You may now utilize the multiplyValues() result to accomplish additional mathematical activities. If you used the print() statement, you wouldn’t be able to complete this operation.
multiplyValues(1,4) product * 2 product = multiplyValues(1,4) product = multiplyValues(1,4) product =
Multiply Values of a Product
The result produced when you use the Python return statement to return output from a function is frequently referred to as explicit output.
Multiple Values Returning
In the same way, you can return multiple values from a Python function by putting one or more comma-delimited values following the Python function return statement.
You could want to construct a function that multiplies two integers and then returns a different message. To do so, set the variable product to the product of the two values, then return the product and message as a single object, as seen below.
Definately multiplied product = param * param2 return product, outputMessage (param,param2,outputMessage) Multiply the message Values(1,4,”Done!”)
Give the Variable Product a name.
Python delivers several values in a function as a Python tuple, which you can then reference specific components of, as seen below.
Definately multiplied product = param * param2 return product, outputMessage (param,param2,outputMessage) Multiply the message output Values(1,4,”Done!”) output[0] output[1]
in a function, return several values
Conclusion
You should now be familiar with Python functions and how to use the Python function return statement. However, this course has only scratched the surface of what Python functions can do.
What do you intend to accomplish with your newly acquired Python function knowledge?
Building Your First AWS Lambda Python Function is a related article.
Functions are a powerful tool in the Python language. They allow you to break down your code into smaller, reusable pieces that can be called by other parts of your program. This tutorial will teach you how to use functions in Python. Reference: how to use functions in python.
Frequently Asked Questions
How do you write a function in Python for beginners?
A: First, you should import the math and string modules. Next, use print to display a message about what is happening in your code block. Then, type help(f) into your console for more information on how to define functions.
What should a beginner learn in Python?
A: This is a difficult question to answer because of the many different uses for Python. In general, it would be best for beginners to learn about variables and data types in Python before diving into other topics like loops or if statements. Its also important that they familiarize themselves with how functions work so they can start writing their own simple scripts using them.
Can a newbie learn Python?
A: Yes. Python is easy to learn, and its not that difficult of a language to get started with. There are quite a few websites out there which explain how to write python code, including this one: https://trypython.org/learn/.
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