Adventures in Machine Learning

The Power of Whitespace in Python Programming: Best Practices and Pitfalls

Python is a powerful and versatile programming language that has gained immense popularity in recent years. From web development to data analysis, Python is used in a wide range of applications due to its simplicity, readability, and ease of use.

In this article, we will delve into some important concepts related to Python statements and line continuation. Whether you are a beginner or an experienced Python programmer, it is essential to understand these concepts to write efficient and error-free code.

Sequential Execution of Statements

One of the fundamental features of Python is that it executes statements in a sequential order. This means that each line of code is executed in the order in which it appears in the script file or interactive session.

This allows programmers to write code that performs a series of operations in a specific sequence. For example, consider the following code:

number1 = 5

number2 = 10

sum = number1 + number2


In this code, the three statements are executed sequentially. First, the variables number1 and number2 are assigned values.

Then the sum of the two variables is computed and stored in the variable sum. Finally, the result is printed to the screen using the print() function.

REPL Session and Script File Execution

Python supports two modes of execution: REPL (Read-Eval-Print Loop) and script files. In a REPL session, you can enter Python code one line at a time and see the results immediately.

This is useful for experimenting with code snippets or testing small pieces of code. On the other hand, a script file contains a sequence of Python statements that are executed as a single unit.

To execute a script file, you can use the command-line interface or an integrated development environment (IDE) such as PyCharm or Visual Studio Code.

One Statement per Line

It is a common practice to write one statement per line in Python code. This makes the code more readable and easier to understand.

For example, the following code snippet is well-formatted and easy to read:

number1 = 5

number2 = 10

sum = number1 + number2


However, some statements can become long and may not fit on a single line. In such cases, we can use line continuation techniques to split the statement into multiple lines.

Implicit Line Continuation

Python has a feature called implicit line continuation, which allows a statement to span multiple lines without using any explicit line continuation character. This is achieved by enclosing the statement in a pair of parentheses, brackets, or curly braces.

For example, consider the following code:

numbers = [1, 2, 3,

4, 5, 6]

In this code, the list of numbers spans multiple lines, but since it is enclosed in square brackets, Python knows that it is a single statement and does not require any line continuation characters.

Usage of Grouping Parentheses

Another way to use line continuation in Python is to use grouping parentheses. This involves enclosing a statement in parentheses and continuing it on the next line.

For example:

sum = (number1

+ number2

+ number3)

In this code, the sum of three variables is computed, and the statement is split into multiple lines using grouping parentheses. Note that the closing parentheses must be on the same line as the opening parentheses, or else Python will raise a syntax error.

Multiple Parentheses, Brackets, or Curly Braces Usage

Python also allows you to use multiple parentheses, brackets, or curly braces to split a statement into multiple lines. For example:

result = func1((arg1, arg2, arg3),

[item1, item2, item3],

{key1: value1, key2: value2})

In this code, the function call spans multiple lines and is split using three sets of parentheses, brackets, and curly braces.

This technique allows complex statements to be split into smaller and more manageable pieces, improving code readability and organization. In conclusion, understanding Python statements and line continuation techniques is essential for writing clean, efficient, and error-free code.

By following best practices such as writing one statement per line and using appropriate line continuation techniques, you can write Python code that is easy to understand and maintain. So the next time you write Python code, keep these concepts in mind and write code that is a joy to read and maintain.

3) Multiple Statements Per Line

Multiple statements per line is a practice that is heavily frowned upon in Python and is considered unPythonic. It is a code style that involves writing more than one statement on a single line.

While the behavior is technically allowed, it is generally not recommended.

Python emphasizes readability over writing concise code.

Multiple statements per line go against this ethos and make the code harder to read and follow, especially for newcomers to the language. It can also lead to unexpected behavior and bugs in the code.

For example, consider the following code:

x = 5; y = 10; z = x + y;


This code assigns values to variables x and y, computes the sum, and prints the result. However, it is not easily understandable at first glance.

The code would be more readable and maintainable if it were written with one statement per line, like the example below:

x = 5

y = 10

z = x + y


Using one statement per line makes the code more organized and easier to understand. It helps to improve code readability and therefore, the code’s maintainability.

So, it’s strongly recommended that developers follow Python’s best practices to ensure that their code is maintainable and readable.

4) Comments

Comments in Python are text annotations that can be inserted into the code to explain the purpose and functionality of the code. They are intended for other programmers, not the computer, to better understand the workings of the code to make it easier to maintain, troubleshoot, and modify.

The Importance of Comments

Comments are essential in Python because they enhance the readability and maintainability of the code. They provide context to the code for other programmers, making it easier to understand the purpose of a particular section of code.

By using comments effectively, programmers can save hours of debugging later on, especially when working on large projects with hundreds or thousands of lines of code.

Single-line Comments

Single-line comments are denoted in Python by a hash symbol (#). They are used to provide a brief explanation of the functionality of a particular line of code.

Single-line commenting is a perfect way to make notes in the code quickly, which wont interfere with the running of the program. For example:

# This is a single line comment in Python

print(“Hello, World!”) # Print the message “Hello, World!”

In the above example, you can see that the first line is a single-line comment that does not affect the execution of the code.

It is used to provide additional information as to what the code does.

Multi-line Comments

Multi-line comments in Python are denoted by triple quotes, also known as a docstring. Based on the context in which the docstring presents itself, it can be accessed through help() function or accessed later as part of the object’s documentation, making them more versatile.

Multi-line comments are used to provide a more detailed explanation of a particular section of the code, a function, or an entire module. By placing a triple-quoted string at the beginning and end of your comment, you can create a multi-line comment in Python.

For example:


This is an example of a multi-line comment in Python.

It can span multiple lines and is used to provide a detailed

explanation of a function, class, or module. “””

Commenting Out Code Using Triple-Quoted Strings

Sometimes, while developing and experimenting with code, you may want to temporarily disable a section of the code without deleting it. Commenting out code becomes an easy way of doing this in Python.

While single-line or multi-line comments work effectively in this case, comments inserted using triple-quoted strings are recommended. By enclosing the code you want to comment out in triple quotes (“”” or ”’), you can effectively comment out large sections of code.

This prevents the code from executing and makes it easier to return to its previous working state later. Using triple-quoted strings is a cleaner and more effective way of commenting out code than single-line or multi-line comments.

For example:


def some_function():

print(“This function does something!”)


In the above example, the code block inside the triple quotes is commented out, meaning it wont execute. This feature is particularly useful for temporary comments, when you anticipate you may need them later in the project.


In conclusion, comments are an essential part of Python programming since they keep an engineering team organized and a single developer on track. They help maintain code quality, making it simple for others to understand, follow, and maintain.

In addition, practicing Python’s best practices, such as coding with one statement per line, can help to ensure that your code is maintainable and readable.

5) Whitespace

In Python programming, whitespace refers to any sequence of spaces, tabs, or blank lines that are used to separate different parts of code. Though optional, their usage is strongly recommended because they help to enhance the readability, organization, and overall quality of the code.

There are certain areas in which whitespace usage is essential in Python.

Use of Whitespace for Readability

In Python, code readability is key to writing better programs. Readable code is easy to understand, reduces errors, and makes maintaining the codebase much simpler.

One of the most common methods to improve code readability is by using whitespace effectively. Proper use of whitespace enhances readability by separating code blocks, grouping related code, and providing visual clarity.

For example, consider the following code snippet:

if score >= 90:

grade = “A”

elif score >= 80:

grade = “B”


grade = “C”

This code is much easier to read and understand than the same code without whitespace. By using whitespace, the code is organized logically, and it is easy to follow the logic of the program.

Importance of Whitespace between Keywords and Identifiers

Another essential area where whitespace is important is between keywords and identifiers. When writing code in Python, it is a good practice to separate keywords and identifiers with whitespace.

Keywords are reserved words in Python that have a special meaning, and identifiers are user-defined names that represent variables, functions, classes, and other objects. Separating the two with whitespace is crucial to allowing the Python interpreter to identify them correctly.

For example, consider the following code:

if score >= 90:

grade= “A”

In this code, the keyword “if” and the identifier “score,” as well as the assignment operator “=” and the string “A,” are not separated with whitespace. This makes the code much harder to read and can be confusing, potentially leading to errors.

Academic Nature of Whitespace Usage

Whitespace is an academic topic in programming languages, and there are different conventions for its usage in different programming languages. While various programming languages have their own specific conventions regarding whitespace, Python takes its whitespace usage more seriously than most languages.

Python’s strong emphasis on the use of whitespace makes it distinct from other languages, allowing for code that is clean, readable, and visually appealing. 6) Deep Dive: Fortran and Whitespace

Fortran is a programming language that has been around for over 60 years and has contributed significantly to the scientific computing and data analysis field.

Unlike Python, Fortran ignores whitespace in the source code. Continuing to treat whitespace in this way often makes older code unsuitable for reuse, updating, and modification.

The practice of ignoring whitespace makes it difficult to read and increases the risk of programming errors, especially in complex code.

Difficulty in Reading and Potential for Errors

When white spaces are ignored, it becomes difficult to distinguish different parts of the program, which often leads to errors, and it has become a significant issue, especially in scientific programming. Though it was widely accepted in the past, programs that ignore whitespace have become difficult to read or modify by the newer generation of programmers.

NASA’s Example of Programming Error Due to Whitespace

NASA once witnessed the dangers of ignoring whitespace when on January 4, 1999, it lost the Mars Climate Orbiter spacecraft due to a programming error. NASA’s investigation revealed the programming error occurred in the spacecraft’s navigation system, where the NASA team was using metric units, while the program was reading them as British Imperial units.

Among other things, the culture of ignoring whitespace was a significant contributing factor to the catastrophic event.


In summary, the use of whitespace is highly recommended in Python because it improves code readability, makes it easier to understand, and reduces errors. The practices of using whitespace are academically accepted and are crucial to the overall sustainability of the code.

As seen with the example of Fortran and the events leading to the loss of the Mars Climate Orbiter, the importance of considering whitespace usage in programming languages can have significant impacts. So when you are writing Python code, ensure to apply the best practices of using whitespace effectively to make the program more maintainable for years to come.

In conclusion, this article has explored various essential topics related to Python programming, including Python statements, line continuation, comments, and whitespace. Python’s emphasis on readability over writing concise code makes the use of whitespace vital in enhancing the organization and readability of the code.

It is crucial to follow the best practices of using whitespace effectively to make your code more maintainable and avoid potential errors. The article has also highlighted how the practice of ignoring whitespace, as seen in Fortran, can lead to difficulty reading code and increases the risk of programming errors.

Remember to use whitespace correctly to make your code stand out and avoid mistakes, ensuring sustainability for years to come.

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