Variables and Data Types

Python uses Dynamic Typing, meaning it determines the data type automatically based on the value you assign to it.

1. Variables

A variable is created the moment you first assign a value to it using the = operator. You can even change a variable's type later in the code (though it's usually better to keep it consistent).

2. Standard Data Types

Python has several built-in data types grouped into these categories:

Category Data Type ExampleNumeric

int, float, complex5, 3.14, 1j

Textstr"Hello"

BooleanboolTrue or False

Sequencelist, tuple, range[1, 2, 3]M

appingdict{"name": "Alice"}

# No need to declare 'int' or 'float'
age = 25              # Integer
price = 99.99         # Float
name = "Python"       # String
is_fun = True         # Boolean (Must be capitalized!)

# You can check the type of any variable using type()
print(type(age))      # Output: <class 'int'>
print(type(price))    # Output: <class 'float'>

# Dynamic reassignment
x = 10
print(x)
x = "Now I am a string"
print(x)

3. Type Casting

If you need to force a variable to be a specific type, you use constructor functions:

• int() - converts to an integer

• float() - converts to a decimal

• str() - converts to a string.

x = int(3.8)    # x becomes 3 (truncates the decimal)
y = str(10)     # y becomes "10"
z = float("5")  # z becomes 5.0

Why this is easier than C:

1. No Memory Management: You don't have to worry about how many bytes an integer takes; Python handles it.

2. Infinite Integers: In C, integers have a limit (overflow). In Python, integers can be as large as your computer's memory allows!