INSTALLING PYTHON
Many PCs and Macs will have python already installed.
To check if you have python installed on a Windows PC, search in the start bar for Python or run the following on the Command Line (cmd.exe):
C:\Users\Your Name>python --version
To check if you have python installed on a Linux or Mac, then on linux open the command line or on Mac open the Terminal and type:
python --version
If you find that you do not have python installed on your computer, then you can download it for free from the following website: https://www.python.org/
Python is an interpreted programming language, this means that as a developer you write Python (.py) files in a text editor and then put those files into the python interpreter to be executed.
The way to run a python file is like this on the command line:
C:\Users\Your Name>python helloworld.py
Where "helloworld.py" is the name of your python file.
Let's write our first Python file, called helloworld.py, which can be done in any text editor.
helloworld.py
print("Hello, World!")
=======o/p=======
Hello, World!
Simple as that. Save your file. Open your command line, navigate to the directory where you saved your file, and run:
C:\Users\Your Name>python helloworld.py
The output should read :
Hello, World!
Congratulations, you have written and executed your first Python program.
To test a short amount of code in python sometimes it is quickest and easiest not to write the code in a file. This is made possible because Python can be run as a command line itself.
Type the following on the Windows, Mac or Linux command line:
C:\Users\Your Name>python
Or, if the "python" command did not work, you can try "py":
C:\Users\Your Name>py
From there you can write any python, including our hello world example from earlier in the tutorial:
C:\Users\Your Name>python
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Which will write "Hello, World!" in the command line:
C:\Users\Your Name>python
Python 3.6.4 (v3.6.4:d48eceb, Dec 19 2017, 06:04:45) [MSC v.1900 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> print("Hello, World!")
Hello, World!
Whenever you are done in the python command line, you can simply type the following to quit the python command line interface:
exit()