Variables in Python

Python is a dynamically typed language.

So, Python doesn't need an explicit variable declaration to reserve memory.

The variable declaration will happen automatically when we assign value to it.


Let's discuss the difference between dynamic typing and static typing.




Dynamic Typing vs Static Typing

Dynamic Typing Static Typing
Variable type checking will happen at runtime. (while executing the code). Variable type checking will happen at compile time. (Before the actual execution).
As the typing checking happens in runtime the dynamically typed code can compile even it has some errors which might lead logical issues. The statically typed code won't compile if it has any error. In order to run the code, we must fix the error.
Dynamically typed languages don't expect the variable declaration before using them. The variable declaration will happen automatically when we assign values to it. Statically typed languages expect the variable declaration before assigning values to it.
Python, Perl, etc. C, Java, etc.

Assigning Values to Variable

Using = operator, we can assign values to the variable.


Example

#Assigning value to variables

name   = "Python"    #string value
age    = 3           #integer value
price  = 0.00        #float value

#Printing values

print(name)
print(age)
print(price)


In Python, there are no values. Everything will be considered as objects.

In the above example, value 3 will not be directly assigned to the variable 'age'.Instead, an integer object with value 3 will be assigned to the variable 'age'.

Similarly, a string object with value "python" will be assigned to the variable 'name' and a float object with value 0.00 will be assigned to the variable 'price'.





Multiple Assignment in Python

we can assign the same object to multiple variables.

Example

#Multiple assignment in python

num1 = num2 = num3 = 0     #initializing num1, num2, num3 to zero

print(num1, num2, num3)


In the above example, an integer object with value 0 will be created and that will be assigned to all the variables. i.e num1, num2, num3

num1, num2, num3 will point the same memory loctaion.




Multi-value Assignment in Python

We can also assign the multiple objects to multiple variables.

Example

#Multi-value assignment in python

name, page_count, price = "Python", 300, 254.65

print(name, page_count, price)


In the above example,

A string object with value "python" will be assigned to the variable 'name'.

An integer object with value 300 will be assigned to the variable 'page_count'

A float object with value 254.65 will be assigned to the variable 'price'.


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