Python Data Types

Python Data Types

Data type of a variable tell us about the data contained by variable and allowed associated operations on it.

Python has following built-in data types: 

• Numbers (int, float, complex, Boolean), 

• None, 

• Sequences (String, List, and Tuples) and 

• Mapping (Dictionary)

a) int (Integer) – Integer represents whole numbers without any fractional part. There are two types of Integers in Python –

i.    Integer (signed) – Whole Number, with unlimited size, depends upon computer memory. Python has single data type (int) for any integer, whether big / long or small.

Example : x = 20

ii. Booleans – These represent truth values False and True. Boolean values are plain integers where False means 0 and True means 1. bool(0) return False, bool(1) returns True.

Example : x = True

b) float (floating point numbers) – Represent real number or floating point number, i.e. numbers with fractional part. A Floating point number in Python can have maximum 53 bits of precision.

Note: 25 is an integer while 25.0 is a floating point number.

Example:  p = 25.908787889

c)    Complex Numbers: Complex numbers in Python are made up of pairs of real and imaginary numbers. Python represents complex number in the form A + Bj, where A is the real part and B is the imaginary part. J or j is the imaginary number, equal to the square root of -1 i.e.    .

A and B both are internally represented as floating point number.

Python displays complex numbers in parentheses when they have a non-zero real part.

Complex numbers are a composite quantity made of two parts: the real part and imaginary part, both of which are represented internally as float values.

These two parts of complex number can be accessed through attributes – real & imag.

• complexNumber.real  - gives the real part as a float

• complexNumber.imag - gives the imaginary part as a float

d) String (str) : A string data type allows us to hold string data i.e. any number of valid characters into a set of quotation marks. In Python 3.x string store Unicode characters.

Example : 

‘125AnjeevSingh’ , “$%@#87Singh Academy”, “??*[],.<>”

In Python, String is a sequence of characters and each character can be individually accessed using its index position.

There are two types of indexing in Python - 

Backward Indexing      0   1    2     3    4     5

                                     A   N   J    E     E     V

Forward Indexing        -6   -5  -4   -3  -2    -1

e) List  - is a list of comma separated values of any data type between square brackets. It can be changed. E.g.

p = [1, 2, 3, 4] m = [‘a’, ‘e’, ‘i’, ‘o’, ‘u’]

q = [“Anjeev”, “kumar”, “singh”]

r = [“Mohit”, 102, 85.2, True]

f) Tuple - is a list of comma separated values of any data type between parentheses. It cannot be changed. Eg.

p = (1, 2, 3, 4) m = (‘a’, ‘e’, ‘i’, ‘o’, ‘u’)

q = (“Anjeev”, “kumar”, “singh”)

r = (“Mohit”, 102, 85.2, ‘M’, True)

g) Dictionary – is an unordered set of comma-separated key : value pairs within curly braces.

rec = {‘name’:“Mohit”, ‘roll’: 102, ‘marks’ : 85.2, ‘sex’: ‘M’, ‘ip’: True}