Autor: Codenga 24.02.2023

Python is one of the most popular choices among novice programmers. Its syntax is simple and very beginner-friendly.

From the point of view of a beginner programmer, even good old relatively simple Python can prove challenging. That’s why we put together this article - full of answers to the most commonly asked questions by programmers in the making :)

1. How to install the Python environment?

Your first step should be to visit the official Python website. If you're just starting out on your journey with Python, it’s best to get the newest and most up-to-date version - at the time of writing this, it’s version 3.11. Take note that there are installers for multiple of the most popular operating systems on the website.

The installation process itself is not hard at all - the specific steps depend on what OS you use. If you use Windows, make sure Python gets added to the PATH environmental variable. This basically means you need to check the respective checkbox during the installation process. It’s a crucial step, and without it you won’t be able to run your code in the command line.

After the installation is done, it’s good to make sure the process was successful. To do that - open the command line and run the command: python. If everything went well, the current installed version of Python should appear (e.g. 3.11).

2. How to create variables and assign them value?

Variables in Python can be created using the following syntax:

variable_name = value

Take a look at this piece of code:

x = 10
y = "Hello World!"
z = [1, 2, 3]

In the example above you can see three variables created: x, y and z. We assigned them values - respectively: 10, “Hello World!” and [1, 2, 3]. In Python you can allow any type of data to variables. In this case the types are:

• numerical
• text (aka. string)
• list (here: a set of three values)

3. How to print data in the console?

Printing data in the console is one of the first things you learn at the beginning of learning Python. You can do it by using the print() function, here’s how:

print("Hello world!")

The function above will make the text “Hello World!” show up in the console.

4. How to write a function in Python?

The example below is a simple function that returns the sum of two given numbers:

def sum(value1, value2):
    result = value1 + value2
    return result


print(sum(2, 3))

In the first line we declared a new function named sum() - it will take in two arguments named value1 and value2. Inside it we created a variable named result - its value is the sum of the two mentioned arguments. At the end we have the return statement, which - well, specifies what value the function is meant to return. Of course we set that to our result value - the value of the summed up arguments.

The result returned by the function for arguments 2 and 3 would be 5.

5. How to debug Python code?

Now, this topic you can approach at multiple different angles. The answer heavily depends on the environment you’re working with. The default way of doing this is using the pdb module, which is a part of the standard built-in Python library. With this module you can track your code’s execution step by step or set what’s known as breakpoints. The module doesn't need any external tools to work properly, it can even be used in the command line :) The bottom line here is - it simply needs to be used in the right place, in the right way. You can find more on this topic in the official documentation.

6. How to handle exceptions in Python?

In Python there is a special instruction that allows you to handle exceptions: try/except. Here's an example:

try:
  print(x)
except:
  print("Exception thrown. x does not exist.")

We have a try block, where we put some code to print out variable x. If such variable doesn't exist (hasn’t been declared), an exception should be thrown. The except block is exactly where you handle these exceptions - usually it comes down to printing out some information about the exception (that it’s been thrown and why).

If the x variable does exist, code in the try block will be executed and the exception will not be thrown.

7. How to import modules in Python?

Modules can be imported with the import instruction. Example:

import math
math.pi

This piece of code will import the entirety of the module named math. It includes many functions and constants that you can access with a period - here we referenced the pi constant, which - as might be expected - stores the value of PI :)

8. How to create a user interface in Python?

To create a user interface (UI) you can use libraries such as PyQt or Tkinter. These libraries contain ready-to-use interface components: buttons, text fields, dialog boxes and many others. They are mainly intended for creating your typical window applications.

Not all apps will have this type of interface though. A lot of Python applications are just simple scripts, ran through the command line. Python can also be used to create web applications, which have HTML and CSS-based interfaces.

9. How to use loops to iterate through sequences in Python?

To iterate through (process) elements of a sequence, you’d usually use the for loop. Take a look:

my_list = [1, 2, 3, 4, 5]


for v in my_list:
    print(v)

Our sequence is a list named my_list. We used the for loop to print all values to console - a single value is being represented by the v value.

10. How to work with files in Python?

Python offers a set of basic built-in functions that allow you to work with files. Using them, you can open and create files, and save data to them. Here's an example:

file = open('my_file.txt')

We used the function open() to open a file named ‘my_file.txt’. We assign the contents of it to the variable file. You have way more functions at your disposal though. You can save data to files by using write(), or you can read data from files using read(). Finally, you can close an opened file with close().