Python: Data Types

Data Type represent the type of data present inside a variable. 

In Python we are not required to specify the type explicitly. Based on value provided, the type will be assigned automatically. Hence Python is Dynamically Typed Language. 

Python contains the following inbuilt 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.None 

1.type() 

to check the type of variable 

2. id() 

to get address of object 

3. print() 

to print the value 

In Python everything is object 

int data type: 

We can use int data type to represent whole numbers (integral values) 

Eg: 

a=10 

type(a) #int 

Note: 

In Python2 we have long data type to represent very large integral values. 

But in Python3 there is no long type explicitly and we can represent long values also by using int type only. 

We can represent int values in the following ways 

1. Decimal form 
2. Binary form 
3. Octal form 
4. Hexa decimal form 

1. Decimal form(base-10): 

It is the default number system in Python 

The allowed digits are: 0 to 9 

Eg: a =10 

2. Binary form(Base-2): 

The allowed digits are : 0 & 1 

Literal value should be prefixed with 0b or 0B 

Eg: a = 0B1111 

a =0B123 

a=b111 

3. Octal Form(Base-8): 

The allowed digits are : 0 to 7 

Literal value should be prefixed with 0o or 0O. 

Eg: a=0o123 

a=0o786 

4. Hexa Decimal Form(Base-16): 

The allowed digits are : 0 to 9, a-f (both lower and upper cases are allowed) Literal value should be prefixed with 0x or 0X 

Eg: 

a =0XFACE 

a=0XBeef 

a =0XBeer 

Note: Being a programmer we can specify literal values in decimal, binary, octal and hexa decimal forms. But PVM will always provide values only in decimal form. 

a=10 
b=0o10 
c=0X10 
d=0B10 
print(a)10 
print(b)8 
print(c)16 
print(d)2 

Base Conversions 

Python provide the following in-built functions for base conversions 

1.bin(): 

We can use bin() to convert from any base to binary 

Eg: 

>>> bin(15) 
'0b1111' 
>>> bin(0o11) 
'0b1001' 
>>> bin(0X10) 
'0b10000' 

2. oct(): 

We can use oct() to convert from any base to octa 

Eg: 

>>> oct(10) 
'0o12' 
>>> oct(0B1111) 
'0o17'
>>> oct(0X123) 
'0o443' 

3. hex(): 

We can use hex() to convert from any base to hexa decimal 

Eg: 

>>> hex(100) 
'0x64' 
>>> hex(0B111111) 
'0x3f' 
>>> hex(0o12345) 
'0x14e5' 

float data type: 

We can use float data type to represent floating point values (decimal values) 

Eg: f=1.234 

type(f) float 

We can also represent floating point values by using exponential form (scientific notation) 

Eg: f=1.2e3 

print(f) 1200.0 

instead of 'e' we can use 'E' 

The main advantage of exponential form is we can represent big values in less memory. 

***Note: 

We can represent int values in decimal, binary, octal and hexa decimal forms. But we can represent float values only by using decimal form. 

Complex Data Type: 

A complex number is of the form 

a and b contain intergers or floating point values 

Eg: 

3+5j 
10+5.5j 
0.5+0.1j 

In the real part if we use int value then we can specify that either by decimal, octal, binary or hexa decimal form. 

But imaginary part should be specified only by using decimal form. 

>>> a=0B11+5j 
>>> a 
(3+5j) 
>>> a=3+0B11j 
SyntaxError: invalid syntax 

Note: Complex data type has some inbuilt attributes to retrieve the real part and imaginary part 

c=10.5+3.6j 

c.real==>10.5 
c.imag==>3.6 

We can use complex type generally in scientific Applications and electrical engineering Applications. 

4.bool data type: 

We can use this data type to represent Boolean values. 

The only allowed values for this data type are: 

True and False 

Internally Python represents True as 1 and False as 0 

b=True 

type(b) =>bool 

Eg: 

a=10 
b=20 
c=a<b
print(c)===>TRUE

True+True==>2 
True-False==>1 

str type: 

str represents String data type. A String is a sequence of characters enclosed within single quotes or double quotes. 

s1='durga' 
s1="durga" 

By using single quotes or double quotes we cannot represent multi line string literals. 

s1="durga 
soft" 

For this requirement we should go for triple single quotes(''') or triple double quotes(""") 

s1='''durga 
soft''' 

s1="""durga 
soft""" 

We can also use triple quotes to use single quote or double quote in our String. 

''' This is " character''' 
' This i " Character ' 

We can embed one string in another string 

'''This "Python class very helpful" for java students''' 

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