The Python print() function

The first step when learning any programming language is typically writing a "Hello, World!" program. This is a simple program that prints the text "Hello, World!" to the screen, and it's an easy way to get comfortable with some of the very basics of Python syntax and running our first piece of code.

In Python, writing "Hello, World!" is incredibly simple - we only need one line of code.

print("Hello, World!")

This single line of code instructs Python to display the message "Hello, World!" on the screen.

Type it into the Python Editor now and run it - you should see the output immediately.

The print() function is the primary way to display output in Python. We can pass it strings, numbers, or expressions:

print(42)      # Output: 42
print(1 + 1)   # Output: 2

We'll often include # Output: ... comments to show expected output.

Multiple arguments

The print() function accepts multiple arguments separated by commas, printing them on one line with a single space between:

print("Taylor", "Swift")  # Output: Taylor Swift

We can also print the value of variables using the print() function. For example:

my_variable = 150
print(my_variable)  # Output: 150

This displays the same as if we had written:

print(150)

We can also print the value of multiple variables, for example:

important_question = "The answer to life, the universe, and everything is"
answer = 42
print(important_question, answer)

Output:

The answer to life, the universe, and everything is 42

Notice how the print() function automatically inserted a space between the values of the two variables.

The print() function has two optional keyword arguments that let us customise its output: sep and end.

The sep argument

By default, when we pass multiple arguments to print(), they are separated by a space. The sep (separator) argument lets us change this:

print("A", "B", "C")  # Output: A B C
print("A", "B", "C", sep="-")  # Output: A-B-C
print("A", "B", "C", sep="")  # Output: ABC

The end argument

By default, print() adds a new line after its output, which is why consecutive print() calls appear on separate lines. The end argument lets us change this:

print("Hello")
print("World")

Output:

Hello
World

But if we change end:

print("Hello", end=" ")
print("World")

Output:

Hello World

Setting end=" " replaced the default new line with a space, so the second print() continues on the same line.

Combining sep and end

We can use both together:

print("A", "B", "C", sep="-", end="!")
print("Done")

Output:

A-B-C!Done

Positioning rule

These keyword arguments must come after all the values we want to print. We'll explore why in more detail when we cover functions in later lessons.

print("X", "Y", sep="-", end="!")  # Correct
print(sep="-", "X", "Y")  # SyntaxError