A variable is a name given to a location in memory. So when you create a variable, you actually reserve some space in the memory and you can store any useful information in that memory location. So we can think of a Python variable similar to a container that stores some useful stuff.
Naming convention to create Python variables
You can choose any name of a variable you like. However, there are certain rules to keep in mind while creating a Python variable. These rules are as follows.
- A variable name must start either with an alphabet or an underscore( _ ).
- The variable name must not contain any whitespace or special characters(@, ^, %, etc).
- The variable name must not be similar to a reserved keyword in Python.
# Valid variable names my_var123 # Valid _Myvar2 # Valid my_var_ # Valid # Invalid variable names 1a # Invalid my@var # Invalid my var # Invalid
Creating variables in Python
Now that we have learned the naming convention, it’s time to create variables. In Python, a variable is created once you assign some value to it. Assigning a value simply means storing some value or data to it. This is done using the assignment operator ( = ).
my_var = 10
The code written above does the following tasks.
- It creates a variable named my_var.
- Reserves some space based on the type of value in the memory.
- Stores value 10 at that memory location.
The operand left to the operator = is the name of the variable and the operand right to the operator = is the value stored in the variable my_var.
Note: Like other programming languages, there is no need to declare a variable in Python. Declaration and assignment both take place at the time of assigning value to the variable.
Now let’s create some more variables and display them.
# A program to create variables in Python my_var1 = 10 my_var2 = "Programmers Portal" my_var3 = 10.23 print(my_var1) print(my_var2) print(my_var3)
Output:
10 Programmers Portal 10.23
Assigning values to multiple variables at a time
Python allows us to assign a single value to multiple variables at a time.
# A program to demonstrate multiple assignments in Python # Assign value 10 to each variable var1 = var2 = var3 = 10 print(var1) print(var2) print(var3)
Output:
10 10 10
Note: You can also assign different values to each variable using a single assignment operator. Refer to the below example:
# A program to demonstrate multiple assignments in Python # Each variable holds different value var1,var2,var3 = 10,'Programmers Portal',20 print(var1) print(var2) print(var3)
Output:
10 Programmers Portal 20
