Python Variables – A Beginner’s Guide

Python is a versatile programming language known for its readability and simplicity. Like most programming languages, it uses variables. Variables are essentially containers that hold data, and they play a fundamental role in Python programming. They allow developers to store and manipulate data. In this article, we will explore Variables in Python.

What is a Variable?

In Python languages, a variable is the name of an identifier that stores the value. This value can be of various data types, such as integers, floating-point numbers, string lists, dictionaries and more. Variables act as placeholders for data that can be used and manipulated throughout your program in python language.

In this section, we will see how to declare and assign variables. You do not need to specify the data type of the variable explicitly. Let’s take an example of declaring and assigning a variable in the Python language.

The following program demonstrates declaring and assigning variables

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Variable Naming Conventions

There are some rules to follow before defining a variable. Variable names must begin with a letter (a-z, A-Z) or an underscore(_). Let’s examine the rules of declaring variables in the Python language.

• Start with a letter or an underscore(_): In Python language, Variable names must begin with a letter (a-z, A-Z) or an underscore(_). It cannot start with a number digit in Python language.

The following example demonstrates the start with a letter or an underscore.

_variable = 10

variable_name = “Python”

• Case sensitivity: Python variables are case sensitive, which means “Age”, ‘age’ and “AGE” are three different variables in Python language.

          For example

• No space allowed: Python variables cannot contain spaces. This variable instead of underscores(_) to separate words in variable names.

For example

• Avoid using reserved keywords: Python developers cannot use reserved keywords, such as ‘if’, ‘else’, ‘while’, ‘for’, or ‘class’, as variable names.
• Use meaningful names: In the Python language, always choose descriptive and meaningful names for your variables. This will make your code more readable and maintainable.

           For example 

Changing Variable Values

In the Python language, variables are dynamic, meaning they can also be changed during the program’s execution. When you assign a new value to the editing variable, the old value can be overwritten.

The following program demonstrates the Changing Variables Values in Python language.

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Python Assigns Values to Multiple Variables

In this section, we will learn “ how to assign multiple variables in one line”  and how to make your code concise and readable.

The following progarm assigns values to multiple variables:

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Assigning Different Values to Multiple Variables

In this section,  python allows adding different values in a single line with “,” operators.

The following program demonstrates the multiple Variables:

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How Does the + Operator Work with Variables?

The Python plus operator +  this operator provides a convenient way to add value If it is a number. If those values are not numbers, then they concatenate the string.

The following program demonstrates the  + operator:

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Global and Local Python Variables

• Local Variables: Local variables are defined and declared inside a function. We cannot use them outside the function.

The following program demonstrates the global and Local Python variable

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• Global Variables: Global variables are those variables that are defined and declared outside a function, and we need to use them inside a function in Python language.

The following program demonstrates the Global Variables

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Global Keyword in Python

The global keyword in Python allows a user to modify a variable outside of the current scope. This keyword is used to create global variables from a non-global scope, for example, inside a function. This allows you to update the global variable’s value from within the function.

Rules of Global Keyword

• In Python, a variable can be assigned anywhere in the program. It’s assumed to be local unless the developer explicitly declares it a global variable.
• Variables that are only referenced inside a function are implicity global in Python language.
• There is no need to use a global keyword in Python language outside a function.

The following program demonstrates the global keyword example in Python language.

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Types of Variables in Python

Python variables can also hold different types of data. There are some common types along with a single example for each type.

• Integers(int):

Integers are whole numbers without a fractional component. The following program demonstrates the variable with an integer type.

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• Floating Point Numbers(float): Python variables also support real numbers. They include a decimal point to represent fractions.

The following program demonstrates the Floating Point Numbers variable.

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• Strings (str): Python variables also can store strings. The string is a character sequence.

The following program demonstrates the Strings variable in Python

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Tom Cruise

• Booleans(bool): Booleans represents two values, true or false.

           The following program demonstrates the booleans.

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• Lists: Lists are the sequence of elements that maintain an order and can contain items of various types.

The following program demonstrates the List of various types.

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• Tuples: Python variable also supports the tuple data initialization.

The following program demonstrates the tuple variable

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• Dictionaries (dict): Dictionaries hold key-value pairs. Keys must be unique and immutable data

The following program demonstrates the unique and immutable.

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• Sets: Sets are unordered collections of unique elements. The following program demonstrates sets with Python variables.

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How to Delete a Variable?

In this section, we will learn how to delete a variable in Python language. Python language automatically removes variables and functions from memory when they are no longer in use. The developer also can remove the variables and functions. This feature is very particularly beneficial when substantial data structures become redundant, as their deletion liberates memory for alternative applications. There is a keyword for removing the variable from the code that keyword is the ‘del’ command in Python language.

The following progarm demonstrates the ‘del’ keyword example.

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Conclusion

In this article, we learned about variable fundamentals in the Python programming language. Variables store data values and are defined using the assignment operator (‘=’). They can have descriptive names following specific rules and can change types dynamically. Variables can store common data types such as integers, floats, strings, lists, tuples, and dictionaries. We also learned about the variable scopes in this article. Understanding variables are essential skill for a Python developer.