Data Types

A data type in Python defines the type of value a variable can store. Python is dynamically typed, meaning you don’t need to specify the data type explicitly—it is determined automatically.

1. Numeric Data Types

Python supports three types of numeric values:

A. Integer (int)

• Stores whole numbers (positive, negative, or zero).
• No decimal point.

Example:

x = 10
y = -5
z = 0
print(type(x))  # Output: <class 'int'>

B. Floating-Point (float)

• Stores numbers with decimal points.

Example:

pi = 3.14
temperature = -10.5
print(type(pi))  # Output: <class 'float'>

C. Complex (complex)

• Used for complex numbers (a + bj format).

Example:

num = 2 + 3j
print(type(num))  # Output: <class 'complex'>

2. Boolean (bool)

• Represents True or False values.
• Used in conditions and comparisons.

Example:

is_raining = True
is_sunny = False
print(type(is_raining))  # Output: <class 'bool'>

Booleans in conditions:

age = 18
print(age >= 18)  # Output: True

3. Sequence Data Types

A. String (str)

• A sequence of characters enclosed in single (') or double (") quotes.

Example:

name = "John"
message = 'Hello, Python!'
print(type(name))  # Output: <class 'str'>

String operations:

text = "Python"
print(text.upper())   # Output: PYTHON
print(text.lower())   # Output: python
print(text[0])        # Output: P (First character)
print(text[-1])       # Output: n (Last character)

B. List (list)

• Ordered, mutable (changeable), and can store multiple types of data.

Example:

fruits = ["apple", "banana", "cherry"]
print(type(fruits))  # Output: <class 'list'>

List operations:

fruits.append("orange")  # Add item
fruits[1] = "grape"  # Modify item
print(fruits)  # Output: ['apple', 'grape', 'cherry', 'orange']

C. Tuple (tuple)

• Ordered, immutable (cannot be changed after creation).

Example:

coordinates = (10, 20, 30)
print(type(coordinates))  # Output: <class 'tuple'>

Tuples are immutable:

# coordinates[0] = 50  # ❌ This will cause an error

D. Range (range)

• Represents a sequence of numbers.
• Used in loops.

Example:

numbers = range(5)  # Generates numbers from 0 to 4
print(list(numbers))  # Output: [0, 1, 2, 3, 4]

4. Dictionary (dict) – Key-Value Pairs

• Unordered collection of key-value pairs.

Example:

student = {"name": "Alice", "age": 20, "grade": "A"}
print(type(student))  # Output: <class 'dict'>
print(student["name"])  # Output: Alice

Modifying a dictionary:

student["age"] = 21  # Update value
student["city"] = "New York"  # Add new key-value pair

5. Set Data Types

A. Set (set)

• Unordered collection of unique elements.

Example:

colors = {"red", "blue", "green"}
print(type(colors))  # Output: <class 'set'>

Set operations:

colors.add("yellow")  # Add an element
colors.remove("blue")  # Remove an element
print(colors)

B. Frozen Set (frozenset)

• Immutable version of a set.

Example:

frozen_colors = frozenset(["red", "blue", "green"])
# frozen_colors.add("yellow")  # ❌ This will cause an error

6. Type Conversion (Type Casting)

You can convert between data types using built-in functions.

Example:

# Convert integer to float
a = 10
b = float(a)  # b = 10.0

# Convert string to integer
num_str = "100"
num = int(num_str)  # num = 100

# Convert list to tuple
fruits = ["apple", "banana"]
fruit_tuple = tuple(fruits)

7. Summary Table

Data Type	Example
Integer (int)	x = 10
Float (float)	pi = 3.14
Complex (complex)	num = 2 + 3j
Boolean (bool)	is_raining = True
String (str)	name = "Alice"
List (list)	fruits = ["apple", "banana"]
Tuple (tuple)	coordinates = (10, 20, 30)
Range (range)	range(5)
Dictionary (dict)	student = {"name": "Alice", "age": 20}
Set (set)	colors = {"red", "blue"}
Frozen Set (frozenset)	frozen_colors = frozenset(["red", "blue"])