Python Variables
A variable is a name which is used to reserve space in memory for storing values.
A variable in Python is created when we assign a value to it.
Here is an example where name, contact_number, amount, and status are variables in which we can store values.
name = "Danny"
contact_number = 987654
amount = 150.60
status = True
print(name)
print(contact_number)
print(amount)
print(status)
The above example gives the following output:
987654
150.6
True
Python is dynamically typed programming language, meaning we do not need to declare the data type of a variable. The type of a variable can also be changed by reassigning a new value of another type to already declared variable.
Example:
name = "Danny"
name = 987654
print(name)
Output:
How to name a variable?
Use small letters and in case of multiple words, separate words with underscore to improve readability.
Example:
first_name = "Danny"
last_name = "Lee"
phone_number = "+1234567890"
email = "[email protected]"
designation = "Python Engineer"
price = 107.45
is_active = True
Variables are Case-Sensitive
In Python, variables are case-sensitive. A variable name a and A are not same but two different variables.
Example:
a = "Hello"
A = 17
print(a)
print(A)
Output:
17
How to find the data type of a variable?
To find the data type of a variable, use type() built-in function.
Example:
first_name = "Danny"
price = 107.45
is_active = True
print(type(first_name))
print(type(price))
print(type(is_active))
Output:
<class 'float'>
<class 'bool'>
To determine whether a variable is of a specific type, use isinstance() function:
Example:
x = "Python"
y = 10
z = True
print(isinstance(x,str))
print(isinstance(y,bool))
print(isinstance(z,bool))
Output:
False
True
