Variables and Data Types

Variables in Python

A variable is a name that refers to a value. Python infers the type automatically, so you never declare it.

name = "Priya"
age = 28
price = 149.99
is_active = True

Core Data Types

• int - whole numbers, e.g. 42.
• float - real numbers, e.g. 3.14.
• str - text, e.g. "hello".
• bool - True or False.
• None - represents no value.
• list, tuple, dict, set - collections.

Working With Strings

first = "Groovy"
last = "Grails"
full = first + " " + last          # concatenation
print(full)
greeting = f"Welcome, {full}!"     # f-string interpolation
print(greeting)

Numbers and Operations

a = 10
b = 3
print(a + b)   # 13
print(a / b)   # 3.333...
print(a // b)  # 3  integer division
print(a % b)   # 1  remainder
print(a ** b)  # 1000 power

Type Checking and Conversion

x = "123"
print(type(x))          # <class 'str'>
y = int(x)              # convert to integer
print(isinstance(y, int))

Key Points

• Python is dynamically typed: types are checked at runtime.
• Use f-strings (f"...{var}...") for clean interpolation.
• int(), float(), str() convert between types.