Python Tutorial 2: How to write your first Python Program by Manish Sharma

Key Takeaways

now that we have installed and configured Python on our machine it's time to learn how to write and execute a program in Python programming language moseub internet i am manish from rebellionrider.com and i am back once again with python programming tutorial in this tutorial we will learn how to write and execute a Python program along with how to clear the Python prompt screen as well as how to exit from the Python prompt so without wasting much of your time let's get started but before that make sure to give this video a thumbs up and subscribe to the channel if you haven't already has many such interesting videos are coming your way now let's start the easiest way of writing and executing a Python code in Windows is through command prompt let's check out how to do that Here I am on my command prompt you can always check the corresponding blog in order to learn how to launch command prompt in case you don't know link is in the description anyways now that we are on the prompt next we have to start the python interpreter to start the python interpreter we are provided with two commands the first command is Python yes just write Python in your command prompt and press Enter that will start your python interpreter the second command is py simply write P Y and then press Enter that will do the same choice is yours go with whichever way you prefer in case your command prompt denies to recognize the Python as an internal command then make sure you have added the Python directory path to the environment variable I have demonstrated how to do that in the previous video you can check that out now let's move ahead and write our first Python program and no it will not be the generic HelloWorld that's what normal people do we are rebellion writers and we code in our own style thus our first program will going to be what's up Internet our favorite string let's write it this single line is an executable statement in this statement we are calling the print function of the Python language and asking it to print the supplied argument on the output screen of the user that supplied argument in our case is our favorite string what's up internet python is not a compiler based language rather it is an interpreter based programming language compiler converts the entire program into the machine language in one go whereas interpreter converts the program by taking a single line at a time which means as soon as you hit the enter the Python engine will straightaway show you the result so let's do it here is our result before moving ahead let me clear a few things for you python is a case sensitive language which means all the function calls which you will be seeing on your screen are different and work differently the first print function call where the name of print function is written in all small letters is the only legitimate function call which will be recognized and executed by the Python interpreter without any error while the rest will raise error let's quickly check we have already seen the working of first function call now let's see what happens if we try to write the print function name in all caps we caught an error named print is not defined now let's check the third function call by trying to write the print function name with capital P let's execute once again the same error hope these demonstrations have clarified that Python is a case sensitive programming language similar to key sensitivity Python is also an indentation sensitive language which means with Python programming language you need to be very careful with your spacebar or tab key a single white space or a mistakenly press the tab key can call Nerra let's do a demonstration suppose unknowingly you pressed the space key before writing the code which in our case will be the print function call let's see what will be the output of it if that happens but first I think we should make some space in our Python prompt so that we can see our code clearly let's scroll a little bit more a little more oh it looks great now let's press the space bar first great now let's start writing our code let's execute as you can see we got an indentation error saying unexpected indent that means you need to be very careful with your spaces in python programming language I think we have made a lot of mass on our Python prompt and it is the best time to learn how to clear the screen of our terminal in Python programming language let's do it we already know that in Windows to clear the command prompt screen we use CLS command right that is exactly what we have to do here but there is a catch we cannot use the host environment command in Python directly you want to check let's do that see what happens when we call CLS command in Python we got an error named CLS is not defined so the question arises here if this is not the correct way then what is let me try to answer that firstly except from using the host environment command which is CLS in Windows and clear and Linux we don't have any other way to clear the terminal screen in Python the only way to use the host command in Python is to use the function system of os interface let me teach you how to do that in order to use the function system we first need to import the OS module simply write the import command this command will import the OS module now we have to call the function system which is defined and declare into this interface using system function of OS module we can run any underlying operating system command that operating system can be Windows Mac or Linux for example in Windows using this function you can run CLS command for clearing the command prompt screen or mkdir for creating a directory for any other dos command you want but for now let's use this function to clear the screen simply write the name of the interface which is OS followed by dot operator and then the name of the function which is system all any small letters as an argument of this function you need to supply the command which you want to run and make sure to enclose this command into a pair of single or double quote we will discuss more about this single and double code concept in a separate video anyways here we have a specified CLS as we want to clear the screen now let's hit the enter button and see the clear screen here you go a neat and clean screen for you guys before winding up this tutorial let's also learn how to exit from the Python shell there are two ways to exit from Python shell the first way is to use the exit function simply write the name of the function along with the parentheses and hit enter this will take you out from the Python shell like this out from the Python another way to exit from Python shell is to use the keyboard shortcut ctrl + Chad let's try that - we are once again in her Python shell to exit from it simply press ctrl + said and then enter once again out from Python that was a quick tutorial on Python language we learnt various small yet useful things here these minut concepts can save you from various errors stay tuned as in the next tutorial we will learn how to create a Python script using IDL e editor please give this video a thumbs up and share it with your friends on your social media thanks for watching this is Manish from rebellion writer calm