Illegal Variable Names In Python

In this tutorial, you will learn about illegal variable names in Python.

It is crucial to learn about these illegal variable names in Python.

As this can help you better understand the programming language.

And will help to write readable, efficient, and error-free code.

An illegal variable name is a name that does not follow the syntax and naming conventions of a specific programming language.

Variable names play a crucial role in creating clear and readable code.

Because variable names help us to represent values or data kept in memory in programming languages.

For instance, in Python, variable names cannot begin with a number, be reserved words or built-in functions, contain spaces or other special characters (other than the underscore “_”), or have punctuation.

Illegal variable naming can result in syntax mistakes or unexpected code behavior.

To make sure that your code is clear, readable, and error-free, it’s crucial to adhere to a programming language’s rules for variable naming.

Illegal variable names in Python can be a huge challenge if you are not aware of them.

Let’s see what makes a variable name illegal in Python.

Variable names cannot start with a number

Variable names cannot start with a number in the majority of programming languages, including Python.

For that reason, a variable name starting with a number is an illegal variable name in Python.

In order to identify and refer to values or data stored in memory, you have to use these variable names.

The first character of a variable name in Python must be a letter or an underscore (_).

And it can then contain any combination of letters, underscores, and numbers.

A variable name’s first character, however, cannot be a number.

In Python, “3days” or “2nd_place” are not acceptable variable names.

However, “my_var” and “_temp” are acceptable.

In Python, a syntax error will appear if you try to create a variable with a name that starts with a number.

Variable names cannot contain spaces or special characters

A variable name containing spaces and special characters is an illegal variable name in Python.

Variable names in Python must begin with a letter or underscore (_), and then may contain any number or combination of numbers, letters, and underscores.

However, variable names cannot contain spaces or special characters like @, #, $,%, &, *, etc.
In Python, “my variable” or “my-var” are not acceptable variable names; however, “my_var” and “_temp” are.

Python will throw a syntax error if you attempt to create a variable with a name that contains a space or other special character.

Therefore, it is crucial to stick to Python’s syntax guidelines for variable names.

Variable names cannot be the same as a Python keyword or built-in function

Certain words or phrases are designated for special use in Python.

These words and phrases are called keywords or built-in functions in programming languages.

You can’t use these terms as variable names because they have a specific meaning or purpose in the language.

For instance, the keywords if, else, while, for, and def have specific meanings in Python.

Similarly, Python’s built-in functions include print(), input(), and len()

You will get a syntax error or unexpected behavior in your code if you try to use a Python keyword or built-in function as a variable name.

Therefore, it’s crucial to pick variable names that are unique and not already taken by Python’s built-in functions or keywords.

You can choose a different name for the variable or add an underscore to it if you want to avoid using Python built-in functions or keywords as variable names.

For instance, you could use “my_if” or “if_” as variable names in place of “if”.

Illegal Variable Names In Python: Using Punctuation

Python does not allow using punctuation in naming variables.

Any variable name that contains punctuation is an illegal variable name in Python.

This is because using punctuation marks in variable names can cause confusion and errors because they are used to indicate special characters or syntax in the language.

Variable names cannot contain punctuation such as periods (. ), commas (,), colons (:), or semicolons ();.

For instance, in Python, “my_var” and “_temp” are acceptable variable names, but “my.var” or “my:var” are not.

Python will throw a syntax error if you attempt to create a variable with a name that contains punctuation.

Variable names cannot be enclosed in quotes, single or double

You can not enclose a variable name in single or double quotes.

This is because using quotes in variable names can cause confusion and errors.

Because quotes are used to define string literals or character constants in Python.

Therefore, any variable name containing a single or double quote is an illegal variable name in Python.

Variable names cannot contain any type of quote, including single and double quotes.

In Python, my_var and _temp, for instance, are acceptable variable names.

Whereas my'var or my"var are not acceptable.

Python will throw a syntax error if you attempt to create a variable with a name that is enclosed in quotes.

As a result, it’s crucial to follow to Python’s syntax guidelines for variable names.

To avoid illegal variable names in Python, you should follow the syntax and naming rules for variable names in the language.

Here are some tips to help you choose legal and meaningful variable names in Python:

Start variable names with a letter or underscore

In Python, variable names must begin with a letter or underscore, followed by any combination of letters, underscores, and numbers.

So, you should always start your variable names with a letter or underscore to avoid syntax errors.

Use descriptive and meaningful names

Variable names should reflect the purpose of the data they represent.

Choose descriptive and meaningful names that make your code easy to understand and maintain.

Avoid using reserved words or built-in functions as variable names

Certain words or phrases are reserved for special use in Python and cannot be used as variable names.

So, avoid using these words as variable names to prevent unexpected errors or behavior in your code.

Use camelCase or underscores for multi-word variable names

If your variable name contains multiple words, you can use either camelCase or underscores to separate the words.

CamelCase capitalizes the first letter of each word after the first, while underscores separate the words with an underscore character.

Avoid using special characters, spaces, or quotes in variable names

Special characters, spaces, and quotes are not allowed in variable names in Python.

So, avoid using them in your variable names to prevent syntax errors.

What are legal and illegal variable names in Python?

Legal variable names in Python are those that follow the syntax rules and naming conventions for variables in the language.

Illegal variable names in Python are those that violate the syntax rules and naming conventions for variables in the language.

Is True an illegal variable name in Python?

“True” is a Python keyword that represents a Boolean value indicating a true condition.

Python does not allow the keyword “True” to be used as a variable name because doing so would result in a syntax error.

All Python keywords, such as “False,” “None,” “and,” “or,” “if,” “while,” “for,” and others, fall under this.

Therefore, it is advised to give your variable a different name that is not a Python keyword.

What is an example of an invalid variable name in Python?

An example of an invalid variable name in Python is “my-var”.

Python does not allow the use of special characters like hyphens (“-“) or other punctuation in variable names.

Instead, Python variable names must begin with a letter or an underscore and may only contain letters, numbers, and underscores.

Another example of an invalid variable name in Python is “1variable”.

In Python, variable names must begin with a letter or an underscore rather than a number.

A syntax error will appear if you try to use these invalid variable names in Python.