Variables in Python
Introduction
In computer programming, a variable is a value that can be changed, depending on conditions or on information passed to the program. They are called variables because their values can vary. In other words, they are not constant. Variables are also used in mathematics and statistics. For example, the average age of American citizens is continually changing and would therefore be considered a variable. Python is a programming language with many features. It has an object-oriented design and can be used in a procedural way. Python is known for its clear syntax and readability. It also supports multiple programming paradigms, including functional and structured programming, as well as OOP.
Definition of variables in python
Variables in Python programming language are used to store data values in a program, such as numbers, strings, and object references. They are an invaluable tool in programming since they allow you to dynamically manipulate values while your program is running, like variables in mathematics that represent different values. In the python programming language, the variables use the same naming conventions as variables used in mathematics: they must start with a letter or underscore, followed by any combination of letters, digits, or underscores. The variables can also be assigned various data types so that it is easier for the interpreter to read and understand what the variable represents. Variables can be initialized with or without a value; if variables have no associated value set when declared, they will hold the None object until it is given another value. Understanding variables in Python programming language goes a long way toward writing meaningful programs efficiently.
How to create variables in python
Creating variables in Python is a simple process, allowing users to assign values to a name that can be called upon later on in the program. Variables have their own data types, such as integers or strings, which are usually written within the same line of code. This can often be done without an explicit declaration. To create a variable, users will simply type the name of the variable followed by an equal sign and then the value it is being assigned for reference. As long as this formula is followed, users should find this process straightforward and easy to incorporate into their programming projects.
There are some steps for creating variables in the python programming language
- To create a variable, use the assignment operator '=' followed by the name of the variable and its desired value.
- Once this is done, the variable is ready to use and will store anything that is assigned to it. For example, integer_variable = 20 creates an integer variable named 'integer_variable' with a value of 20.
In addition, the developer as well as the user can also assign strings, classes, and objects as values for that particular variable. Python is known for being easy to learn and comprehend, so creating variables should not be too difficult. Knowing how to create variables properly can make or break a program or script; be sure that each type of data is assigned to the correct variable accordingly for ultimate program accuracy.
How to print variables in python
Printing variables in python is a simple process that anyone can do with some basic python knowledge. Using the print command allows you to take any python variable and output it in the command line or terminal window. The user only has to do is use the python print statement and add the variable after it. The python interpreter will convert the variable into its representation when outputted to the screen, whether it be a string, number, list, etc. If the user wants to get more specific with how what should be printed out there are formatting options that can be used, such as printing only a certain number of decimals for floats or splitting strings, but all of this stems from the fundamental python print command syntax. With just this one command, python users can easily print out the data they want without having to jump through too many hoops.
How to delete a variable in python
Deleting a variable in python is easily achievable with the del statement. Del can be used to delete variables, lists, and dictionaries within a program. It is important to note that you cannot delete a variable permanently; instead, you delete the reference to the object that the name was bound to. The best practice when it comes to deleting variables in python is to delete its reference by using the del keyword if it is no longer needed as this will prevent any accidental references to the variables later on in the code. By deleting references of unwanted variables you can streamline your code and keep your programs running efficiently.
Example
counter = 100
print (counter)
del counter
print (counter)
Output
100
Traceback (most recent call last):
File "main.py", line 5, in <module>
print (counter)
NameError: name 'counter' is not defined
Multiple Assignment
Multiple Assignment in python is a powerful technique for assigning more than one value to multiple variables at once. Multiple Assignment allows for a shorthand method of declaring multiple variables without having to type out each assignment statement separately. Multiple assignment can be beneficial when dealing with large data sets or types that require multiple values to be assigned, as it significantly streamlines the process and saves time.
Example
a,b,c = 1,2,"Scholar Hat"
print (a)
print (b)
print (c)
Output
1
2
Scholar Hat
Python Variable Naming Conventions
In the python programming language, every variable should have a unique name such as a, b, c. A variable name can be significant like name, age, address, etc. There are certain rules that a developer needs to follow while naming a Python variable, those are:
- In python language, a variable name starts with a letter or any underscore character
- In this language, a variable name cannot start with a number or any special character such as $, (, * %, etc.
- A variable name in python language only contains alphabetical and numeric characters and underscores, such as A-z, 0-9, and _
- Python variable names vary for uppercase and lowercase which means “Name” and “NAME” are two different variables in Python.
- The reserved keywords in a python programming language cannot be used for naming any variable.
Example
counter = 100
_count = 100
name1 = "Urmi"
name2 = "Bose"
Age = 20
urmi_salary = 100000
print (counter)
print (_count)
print (name1)
print (name2)
print (Age)
print (urmi_salary)
Output
100
100
Urmi
Bose
20
100000
Local and Global Variables in Python
There are two types of variables in the python programming language, which are
- Python local variable
- Python global variable
Python Local Variable
Python Local Variables are one of Python's best features because they offer so much flexibility. Python Local Variables allow for assigning values to a variable within a specific context, like a program or function. Python does not require that you explicitly declare the type of variable that is being used; instead, Python assigns values based on the first kind of object assigned. This functionality makes programming in Python versatile and efficient as Python code can be automatically adapted to various data types allowing programmers are able to write fewer lines of code without compromising quality or clarity.
Example
def sum(x,y):
sum = x + y
return sum
print(sum(5, 10))
Output
15
Python Global Variable
Python Global Variable is an incredibly useful tool for Python programmers. Python Global Variable allows for data to be shared across various Python files, making it much easier to work with different variables within a program. This is especially helpful in complex applications where a single Python file may have several different variables being used throughout the program. Python Global Variables provide a way to quickly and easily access them without having to rewrite the same code multiple times. The real advantage of using Python Global Variables over other methods is the flexibility they allow; it is possible to change their values at any point in the program without breaking existing code. Python Global Variables are often essential tools when developing complicated programs, making them quite invaluable for Python programming in general.
Example
x = 5
y = 10
def sum():
sum = x + y
return sum
print(sum())
Output
15
Summary
In this blog post, we covered variables in python. We learned that variables are used to store values, and they are classified by their type. While the number of ways you can use variables in your Python programs may seem daunting at first, they provide a powerful tool for streamlining your code. By taking the time to learn about the different types of variables and how to use them effectively, you can make your Python programming faster, easier, and more efficient. We also discussed how to choose informative variable names, and how to use the print() function to debug our code. Finally, we saw how comments can be used to make our code more readable for other people. By understanding how to use variables correctly, we can write cleaner and more efficient code. Do you have any tips for using variables in Python? Let us know in the comments below!
Take our free skill tests to evaluate your skill!
In less than 5 minutes, with our skill test, you can identify your knowledge gaps and strengths.
Previous Tutorial
