Data Types

Built-in Data Types in Python

1. Integers (int)

Whole numbers, positive or negative, without decimals.

x = 10
type(x)   # <class 'int'>

2. Floating-Point Numbers (float)

Numbers containing decimals or written in exponential notation.

pi = 3.15
type(pi)   # <class 'float'>

3. Complex Numbers (complex)

Numbers with a real and imaginary part.

c = 6 + 8j
type(c)   # <class 'complex'>

a, b = 2, 3
c = complex(a, b)  # (2+3j)

Python uses j (not i) to represent the imaginary unit.

4. String Type (str)

A sequence of characters enclosed in quotes.

name = 'muskan'
type(name)   # <class 'str'>

5. Boolean Type (bool)

Booleans represent truth values: True or False. They commonly result from comparison operations.

a, b = 7, 6
greater = b > a
print(greater)   # False

6. None Type (NoneType)

None represents the absence of a value, similar to null in other languages.

result = None
print(result)   # None

Type Conversion

• Python provides built-in functions like int(), float(), and complex() to convert data types.

• Converting float → int truncates decimals (does not round).
• Converting int → float simply appends .0.

a = 5.6
b = int(a)       # float → int
print(b, type(b))  # 5 <class 'int'>

k = float(b)     # int → float
print(k, type(k))  # 5.0 <class 'float'>

c = complex(4, 5)  # create complex number
print(c, type(c))  # (4+5j) <class 'complex'>

• Booleans can be converted into integers:

• True → 1
• False → 0

print(int(True))   # 1
print(int(False))  # 0
print(float(False)) # 0.0

Sequence Data Types

Python provides multiple built-in collection types:

1. List (list)

• Ordered, mutable collection.
• Enclosed in [ ].
• Allows duplicates.

l = [4, 5, 6, 7]
type(l)   # <class 'list'>

2. Tuple (tuple)

• Ordered, immutable collection.
• Enclosed in ( ).
• Useful for storing data that should not change.

t = (4, 5, 6, 7)
type(t)   # <class 'tuple'>

3. Set (set)

• Unordered, mutable, collection of unique elements.
• Enclosed in .
• Removes duplicates automatically.

s = {4, 5, 6, 4}
type(s)   # <class 'set'>

4. Range (range)

• Represents a sequence of numbers.
• Immutable, commonly used in loops.

r = range(10)
set(r)  # {0,1,2,3,4,5,6,7,8,9}

The general syntax is:

range(start, stop, step)

• start → beginning of the sequence (default = 0)
• stop → end of the sequence (excluded)
• step → difference between consecutive values (default = 1)

You can also generate custom sequences by specifying all three parameters:

set(range(2, 11, 2))   # {2, 4, 6, 8, 10}

Summary

• Python is dynamically typed, meaning variable types are assigned automatically based on the value.
• Core data types include numbers (int, float, complex), strings, booleans, and None, with type conversions.
• Python support sequence data types:
  • List (mutable, ordered)
  • Tuple (immutable, ordered)
  • Set (mutable, unordered, unique elements)
  • String (immutable sequence of characters)
  • Range (immutable sequence of numbers)