Variables in Python
- A variable is a symbolic name that references a value in memory.
- In Python, variables are used to store data values.
- They act as labels for memory locations, allowing you to access and manipulate data easily.
- In Python, you don’t have to specify the data type of a variable because it is automatically determined based on the assigned value.
Example
Python
# Variable assignment
name = "Kunal"
age = 17
height = 5.6
# Variable usage
print("Name:", name)
print("Age:", age)
print("Height:", height)
Variable Naming Rules
- Variable names must start with a letter (a-z, A-Z) or an underscore (_).
- The rest of the variable name can consist of letters, numbers (0-9), and underscores.
- Variable names are case-sensitive (kunAl and kunal are different variables).
Assigning Values
- You can assign values to variables using the assignment operator (=).
- The variable on the left of the = sign receives the value on the right.
Python
a = 50
b = 60
total = a + b
Multiple Assignment:
You can assign multiple variables on a single line.
Python
a, b, c = 10, 20, 30
Swapping Values:
Python allows you to swap the values of variables without using a temporary variable.
Python
a, b = 10, 20
a, b = b, a # Swap values: a = 20, b = 10
Global vs. Local Variables:
- Variables declared outside functions are known as global variables. They can be accessed from anywhere within the program.
- On the other hand, variables declared inside functions are called local variables. They are only accessible within that specific function.
Python
global_var = 10
def my_function():
local_var = 20
print(global_var) # Access global variable
print(local_var) # Access local variable