Tutorial

Python is a very simple language, and has a very straightforward syntax. It encourages programmers to program without boilerplate (prepared) code. The simplest directive in Python is the “print” directive - it simply prints out a line (and also includes a newline, unlike in C).

There are two major Python versions, Python 2 and Python 3. Python 2 and 3 are quite different. This tutorial uses Python 3, because it more semantically correct and supports newer features.

For example, one difference between Python 2 and 3 is the print statement. In Python 2, the “print” statement is not a function, and therefore it is invoked without parentheses. However, in Python 3, it is a function, and must be invoked with parentheses.

To print a string in Python 3, just write:

print("This line will be printed.")

Indentation

Python uses indentation for blocks, instead of curly braces. Both tabs and spaces are supported, but the standard indentation requires standard Python code to use four spaces. For example:

x = 1
if x == 1:
    # indented four spaces
    print("x is 1.")

Exercise

Use the “print” function to print the line “Hello, World!”.

print("Goodbye, World!") print("Hello, World!") test_output_contains("Hello, World!") success_msg('Great job!')