Coding has become important pillar of literacy among today’s students, and Python has emerged has top coding language which is used by school going students in US, India and other countries.
Coding is when you interact with computer with given inputs, instructions to give an output or solve a particular problem. The output given by computer is based on the instructions, and the algorithm which is running in the computer.
Computer understands the input in the form of variables. Variables are contains which store information data. This data is initialized by user giving commands, and it often change values once computer program is run.
The variable data gets updates whenever our program executes. When we assign a value to a variable, we use that variable in our programming to store result, or assist in performing a certain operations.
For example, if variable is month of the year based on date. So, based on the date when the program run, this variable changes values. It will become January if it runs on January 10, it will become April, if it run on April 25. As you can see, this variable is dependent on the current date, and it changes values whenever month changes.
Following python program is updating month based on current date
Why Are Variables Important?
Variables serve several important purposes in programming:
- Data Storage: Variables hold information that program can use. This information is used in the giving output, or executing key functions in program. This information is also stored in database.
- Code reusability – Without variables, every time you needed a value, you’d have to type it out, making coding unnecessarily complicated. Variable avoids duplicity of work, and solve code redundancy issue. This makes programs small, and easy to understand.
- Code readability: Well-named variables make your code easier to understand. Instead of a series of numbers or hard-to-understand terms, you can use descriptive names to make your code more intuitive.
Python rules for declaring variables
Let’s understand important rules for declaring variables in Python coding.
- A variable name must start with a letter (a-z, A-Z) or an underscore (_)
- Variable names cannot contain spaces
- After the first letter or underscore, the variable name can contain letters, numbers (0-9), or underscores
- Besides underscores, you can’t use symbols like @, $, or # in variable names.
- Variable names are case-sensitive, which means value and Value are different variables
- Variable names cannot be Python keywords or reserved words (e.g., if, else, for, class, etc.)
- Variable names cannot start with number
Examples of variables in Python
Variable Datatype in Python
In Python, variable can store different types of values. This is defined by datatype which tell identity of variable. Unlike other programming languages, Python programming does not need declaring data type in front of variable name, and it autopick variable datatype based on the value of the variable. Variable datatypes once declared cannot be changed.
- Integer (int): A whole number (e.g., 10, -5, 100).
- Floating-point (float): A number with a decimal point (e.g., 3.14, 7.5).
- String (str): A sequence of characters (e.g., “hello”, “Python”).
- Boolean (bool): A value that is either True or False.
Different Data Types in Python
# Storing different types of data
- age = 15 # Integer
- height = 5.8 # Float
- name = “Ethan” # String
- is_student = True # Boolean
# Displaying the data
- print(“Age:”, age)
- print(“Height:”, height)
- print(“Name:”, name)
- print(“Is student:”, is_student)
Using Variables in Python
In Python, we can perform various operations on variables, depending on the type of the data stored in the variable (e.g., integers, strings, lists, etc.).
Arithmetic Operations on Numeric Variables
For variable containing integer or float datatype, we can do mathematical operations like addition, subtractions, multiplication and division.
Comparison of variable
We can compare variable in Python to check whether they are equal, more than or less than other variable
- variable1 = 10
- variable2 = 20
- print(variable1==variable2)
- print(variable1>variable2)
- print(variable1<variable2)
Logical operations
In logical operations, variables are combined with other variable in the execution of program.
Common logical operations are AND, OR, NOT
String operations
In Python language, string operations are most common used in program and printing output
Best Practices for Using Variables in Python
Here are some important tips while using variable in python programming
- Use descriptive names, ideally in snake_case.
- Don’t use reserved keywords or built-in function names.
- Avoid starting variables with numbers.
- Do not use spaces in variable names.
- Follow consistent naming conventions for readability.
Conclusion
In this article, we saw how important variables are in Python programming language. We also learn about different rules in declaring python variables, and saw different variable types.
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