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Data Types in Python

What is a Data Type?

A data type defines:

  • The type of value stored in a variable
  • The operations that can be performed on it

Example

a = 10

Here:

  • a → variable
  • 10 → integer value
  • int → data type

Dynamic Typing in Python

Python is a dynamically typed language. This means:

  • You do not declare data types explicitly
  • A variable can be reassigned to a different type

Example

a = 10
print(a)

a = 10.5
print(a)

✅ Valid in Python ❌ Not allowed in statically typed languages like C or C++

Checking the Data Type

Use the built-in type() function.

a = 10
print(type(a))   # <class 'int'>

a = 10.5
print(type(a))   # <class 'float'>

Object Identity (Memory Address)

Python stores objects in memory, and variables reference them.

To check the memory address, use id().

a = 10
print(id(a))

📌 This helps understand immutability in Python.

Built-in Data Types in Python

Python has 14 built-in data types:

  1. int
  2. float
  3. complex
  4. bool
  5. str
  6. bytes
  7. bytearray
  8. range
  9. list
  10. tuple
  11. set
  12. frozenset
  13. dict
  14. NoneType

1️⃣ Integer (int)

Integers are whole numbers (positive, negative, or zero).

a = 10      # ✅ int
a = -100    # ✅ int
a = 10.5    # ❌ not int

Python 2 vs Python 3

  • Python 2 had int and long
  • Python 3 has only int
  • Large numbers are handled automatically
a = 1234293864389456348756348745896745879
print(type(a))   # <class 'int'>

Integer Number Systems

Python supports integers in four number systems:

System Base Allowed Digits Prefix
Binary 2 0, 1 0b
Decimal 10 0–9 (default)
Octal 8 0–7 0o
Hexadecimal 16 0–9, A–F 0x

Binary Example

a = 0b1010
print(a)      # 10

Octal Example

a = 0o1010
print(a)      # 520

Hexadecimal Example

a = 0xFACE
print(a)      # 64206

Base Conversion Functions

Function Converts to
bin() Binary
oct() Octal
hex() Hexadecimal

Example

a = 0xFACE

print(bin(a))
print(oct(a))
print(hex(a))
print(a)       # Decimal (default)

Negative Number Example

a = -15
print(bin(a))

2️⃣ Float (float)

A float is a number with a decimal point.

a = 1.45
print(type(a))   # <class 'float'>

Example

a = 14
print(type(a))   # int

b = 34.56
print(type(b))   # float

Exponential (Scientific) Notation

Python supports exponential notation using e or E.

a = 1.2e3
print(a)         # 1200.0
print(type(a))   # float

Meaning:

1.2e3 = 1.2 × 10³

❌ Invalid Operations with Float

Floats cannot be represented in binary, octal, or hexadecimal form.

a = 1.5
bin(a)    # ❌ TypeError

❌ Also invalid:

a = 0b1.1
a = 0o1.1
a = 0x1.1

Next: Complex, Boolean, String, Type Casting & Immutability in Python