Data Types in Python Programming

Data Types

Ø  Data Type represents the type of data present inside a variable.

Ø  In Python we are not required to specify the type explicitly.

Ø  Based on value provided, the type will be assigned automatically.

Ø  Hence Python is Dynamically Typed Language.

Python contains the following inbuilt data types

1. int	4.bool	7.bytearray	10.tuple	13.dict
2. float	5.str	8.range	11.set	14. None
3.complex	6.bytes	9.list	12.frozenset

Note: Python contains several inbuilt functions

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 an object

int Data Type:

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

Example: >>> a=10                            >>> a=40+60

               >>> type(a)                          >>> a

               <class 'int'>                          100

Note:

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

Ø  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):

Ø  It is the default number system in Python.The allowed digits are: 0 to 9

Example : >>> d=528                          >>> d=1234a

                  >>> d                                >>> d=1234a

                        528                                     File "<stdin>", line 1    d=1234a         

                                                                                                             ^SyntaxError: invalid syntax

  2. Binary form(Base-2);

Ø  The allowed digits are: 0 & 1.Literal value should be prefixed with Ob or OB

Example :>>> b=0b1111                    >>> b=0B123

                >>> b                                 File "<stdin>", line 1    b=0B123        

                       15                                ^SyntaxError: invalid digit '2' in binary literal3

3. Octal Form(Base-8);

Ø  The allowed digits are: 0 to 7,Literal value should be prefixed with 00 or 00.

Example: >>> o=0o1234      >>> o=0O143

                 >>> o                    >>> o

                        668                       99

              >>> o=0O148

                     File "<stdin>", line 1    o=0O148

                                                                        ^SyntaxError: invalid digit '8' in octal literal

4. Hexa Decimal Form(Base-16);

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

Example:>>> h=0x123f                            >>> h=0X123e

               >>> h                                        >>> h

                      4671                                           4670

>>> h=0X14h

  File "<stdin>", line 1    h=0X14h

                                                     ^SyntaxError: invalid syntax

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.

2.float Data Type:

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

Example :.>>> f=1.234                >>> f = 1.2e3      >>> f = 3.4E2    >>> type(f) 

               >>> f                            >>> f                     >>> f                      <class 'float'>

                      1.234                             1200.0                   340.0

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

Ø  Instead of 'e' we can use 'E'

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

Note:

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

>>> f=0B11.01

  File "<stdin>", line 1    f=0B11.01         

                                                    ^Syntax Error: invalid syntax

x = 35e3

y = 12E4

z = -87.7e100

print(type(x))     #<class 'float'>

print(x)              #35000.0

print(type(y))   #<class 'float'>

print(y)           #120000.0

print(type(z))   #<class 'float'>

print(z)            #-8.77e+101

3. complex Data Type:

Ø  A complex number is of the form

a           +     bj

Ø  Real Part Imaginary Part

Ø  a and b contain integers or floating point values

Examples :3+5j 10+5.5j  0.5+0.1j

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

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

>>> a=0B11+5j

 >>> a

 (3+5j)

 >>> a=3+0B11j

 Syntax Error: invalid syntax

Ø  Even we can perform operations on complex type values.

1) >>> a=10+1.5j

 2) >>> b=20+2.5j

 3) >>> c=a+b

4) >>> print(c)

5) (30+4))

6) >>> type(c)

7) <class 'complex'>

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

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

4. bool Data Type:

Ø  We can use this data type to represent boolean values. The only allowed values for this data type are:True and False

Ø  Internally Python represents True as 1 and False as 0

b=True

type(b)

 =>bool

a=10

b=20

c=a<b

print(c)==>True

True+True==>2

True-False==>1

5. str Data Type:

Ø  str represents String data type.

Ø  A String is a sequence of characters enclosed within single quotes or double quotes.

s1='siddu' s1="siddu"

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

s1="siddu

                                 soft"

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

            s1=’’’siddu soft’’’   s1="""siddu soft"""

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

             ""This is " character"" 

             'This is" Character'

Ø  We can embed one string in another string ""This "Python class very helpful" for java students""

ü  In Python the following data types are considered as Fundamental Data types

             1. int      2. float          3. complex                   4. bool             5 .str

ü  In Python, we can represent char values also by using str type and explicitly char type is not available.

Example:

 >>> c='a'

 >>> type(c)

 <class 'str'>

ü  long Data Type is available in Python2 but not in Python3. In Python3 long values also we can represent by using int type only.

ü  In Python we can present char Value also by using str Type and explicitly char Type is not available.