Your First Python Program
What Python is, how to install it, and how to make the computer say hello.
Python is a general-purpose programming language that was designed to be easy to read. Its code uses plain words such as if, for and return, and it uses indentation (spaces at the start of a line) instead of curly braces to group code together. That is why many schools and universities choose it as a first language.
Setting up Python
You can run Python in two common ways:
- Install it locally. Download the installer from python.org, run it, and tick the option that adds Python to your PATH. Then open a terminal and type
python --versionto check it worked. - Use an online editor. If you cannot install software right now, any online Python editor is fine for these lessons.
Hello, world
The tradition in programming is to start by printing a greeting. Save this line in a file called hello.py:
print("Hello, world!")Hello, world!
Run it from a terminal with python hello.py. The print() function writes whatever you put inside the brackets to the screen. Text in quotes is called a string.
Printing more than one thing
print() can take several values separated by commas. It puts a space between them and moves to a new line at the end.
print("Learning", "Python", "is", "fun")
print("2 + 3 =", 2 + 3)
print() # an empty print gives a blank line
print("Done!")Learning Python is fun 2 + 3 = 5 Done!
Anything after a # is a comment. Python ignores comments, so you can use them to leave notes for yourself and for other readers.
What you learned
- Python programs are plain text files ending in
.py. print()shows values on the screen.#starts a comment.