Writing Our First Code

Get familiar with using print statements, comments, and docstrings.

We'll cover the following

Let's get started with the fun stuff by diving directly into code.

The print() function

When learning any new programming language, a common tradition is to start by displaying the text "Hello, World!" on the screen. Each language has its own syntax for outputting or printing information. Python, known for its readability, makes this task simple by using the print() function.

Here’s how the print() function works in Python:

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print("Data to be printed")

All content to be printed is enclosed within the parentheses that follow the print keyword. Now, let’s attempt to print “Hello World” in the terminal.

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print("Hello World")

It's important to note that the text Hello World is enclosed in quotation marks because it represents a string, which is a sequence of characters.

Next, we’ll print some numbers. Each call to print will move the output to a new line.

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print(50)
print(1000)
print(3.142)

Did you notice that we haven't enclosed the numbers inside quotation marks? If we had done that, the interpreter would have treated the numbers as strings. The difference between the two will become more clear when we discuss data types.

Printing multiple pieces of data

We can print multiple items in a single print command by simply separating them with commas.

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Print statement
Print statement

Try it yourself

See if you can repair the following code and make it run successfully. Our AI Mentor can guide you as well.

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print(50, 1000, 3.142 "Hello World"

By default, each print statement prints text in a new line. If we want multiple print statements to print in the same line, we can use the following code:

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

The value of end is added to the output, and the next print statement will continue from that point.

Comments

Comments are pieces of text used to describe what is happening in the code. They have no effect on the code whatsoever. However, comments in coding serve several important purposes. They enhance code readability, and make it easier to understand, debug, and maintain code. In large teams, comments facilitate collaboration because team members can use them to understand each other’s code, as well as their own code.

Best practices for writing comments:

  • Comments should be accurate, clear, to the point, and meaningful—explaining the code's functionality in a way that is easy to understand.

  • The level of detail in comments can vary depending on the complexity of the code—ranging from a one-liner for simpler code to a more detailed explanations for intricate algorithms.

  • Maintain a consistent style and formatting for your comments throughout the codebase for better readability.

A comment can be written using the # character in Python. The following code widget shows how to write single line comments. Note that each line of comment needs to start with the # character.

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print(50)  # This line prints 50
print("Hello World")  # This line prints Hello World
# This is just a comment hanging out on its own!
# For multi-line comments, we must
# add the hashtag symbol
# each time

An alternative to these multi-line comments are docstrings—short for documentation strings. They are encased in triple quotes, ''', and can be used to replace multi-line comments.

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''' Docstrings are pretty cool
for writing longer comments
or notes about the code '''
print(50)  # This line prints 50
print("Hello World")  # This line prints Hello World

In Python, comments and docstrings serve different purposes:

  • Comments are used to explain specific lines or blocks of code. They are meant for developers to understand the logic and intent behind the code. They are not executable. Use comments to clarify complex code, note assumptions, and highlight important points.

  • Docstrings take a broader view of different components of your code and are used to provide documentation at a more macro level. They are accessible via the help() function and are meant to describe the overall purpose and usage of the code. According to the Python Style Guide, each script and all publicly accessible pieces of code should have a docstring at the beginning to guide users on how to use the code effectively.