Understanding Variables in Python

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In the previous post, I explained how to use comments. Now, in this article, I will discuss Python variables.

What Are Python Variables?

In maths, we say a variable is a reference point where we actually store a number for doing some operation. Similarly, in a programming language, a variable is a container (storage area) to hold data. For example,

pyhog = 10

Here, pyhog is a variable storing the value 10.

We assign those values using the assignment operator =.

So, any value we can assign.

Assigning Values to Variables in Python

As we can see from the above example, we use the assignment operator = to assign a value to a variable.

Another example where we are storing normal words:

blog = 'dev.to'

print(blog)

# Output: dev.to

Here, we assigned a value inside '' and we print that value using that variable name.

Python is a type-inferred language, so you don't have to explicitly define the variable type. It automatically knows that dev.to is a string and declares the blog variable as a string.

Changing Variable Value

We can actually update the value accordingly.

blog = 'dev.to'

print(blog)

# Output: dev.to

blog = 3

print(blog)

# Output: 3

As Python handles variables dynamically, it allows us to update an int with a string variable holder.

Rules for Naming Variables

There are a few rules which all developers should follow to have some structured code instead of random words.

Each variable should have its meaning.

For example, if I want to store the score of a team, we will use score but not count.

There are many things we actually define.

Other than these meaningful variable naming conventions, we have these rules:

1. Constant and variable names should have a combination of letters in lowercase (a to z) or uppercase (A to Z), digits (0 to 9), or an underscore (_).

snake_case
MACRO_CASE
camelCase
CapWords

1. Create a name that makes sense. For example, score makes more sense than i.

2. If you want to create a variable name having two words, use an underscore to separate them.
   

my_name
current_salary

1. Python is case-sensitive. So, num and Num are different variables. For example,

var score = 3 
var Sum = 90
print(num) # 3
print(Num) # 90

1. Avoid using keywords like if, True, class, etc. as variable names.

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