Python Data Types

byMy Scribble Pads •August 11, 2025

Python Data Types — Notes

1. Overview

A data type defines the kind of value a variable holds.
Python is dynamically typed — no need to declare the type explicitly.
Use type() to check a variable’s type:
```
x = 10
print(type(x))  # <class 'int'>
```

2. Basic Data Types

a) Numeric Types

Integer (int)
- Whole numbers (positive, negative, zero)
- Example:
```
a = 5
b = -10
```
Floating Point (float)
- Numbers with decimal points
- Example:
```
pi = 3.14
```
Complex Numbers (complex)
- Numbers with a real and imaginary part
- Example:
```
c = 2 + 3j
```

b) Text Type

String (str)
- Sequence of characters inside quotes
- Example:
```
name = "Python"
```

c) Boolean Type

Boolean (bool)
- Represents True or False
- Example:
```
is_active = True
```

3. Collection Data Types

a) List

Ordered, changeable (mutable)
Allows duplicate values
Example:
```
fruits = ["apple", "banana", "cherry"]
```

b) Tuple

Ordered, unchangeable (immutable)
Example:
```
coordinates = (10.0, 20.0)
```

c) Set

Unordered, unique items
Example:
```
unique_nums = {1, 2, 3}
```

d) Dictionary

Key-value pairs, unordered
Example:
```
person = {"name": "Alice", "age": 25}
```

4. None Type

None represents absence of value

data = None

5. Type Conversion (Casting)

x = int("10")     # str → int
y = float(5)      # int → float
z = str(3.14)     # float → str

6. Checking Type

print(type(5))           # <class 'int'>
print(isinstance(5, int))  # True

Tags: Python Python Core