Data Types in python

Data Types

• Data types are used to define a type of variable.

• In python there are five types of data type that are used commonly and those are ‒

Fig. 1.5.1 Data types in python

1) Numeric:

Python numeric data type is used to hold numeric values like;

■ int ‒ Holds signed integers of non‒limited length.

■ long ‒ Holds long integers.

■ float ‒ Holds floating precision numbers and it's accurate upto 15 decimal places.

■ complex ‒ Holds complex numbers.

 In python we need not to declare data type while declaring a variable like C or C++. We

can simply just assign values in a variable. But if we want to see what type of numerical value it is holding right now, we can use type(). For example ‒

2) String:

■ String is a collection of characters.

■ In python, we can use single quote, double quote or triple quote to define a string.

■ We can use two operators along with the string one is + and another is *.

■ The operator is used to concatenate the two strings. While *operator is used repetition operation. Following execution illustrates it‒

In [5] :

str1 = "My"

str2 = "Phython"

print(str1)

print(str2)

My

Phython

3) List:

■ It is similar to arrays in C or C++ but it can simultaneously hold different types of data in a list.

■ It is basically an ordered sequence of some data written using square brackets([]) and commas(,)

■ For example –

In [8]: #List of only integers

a = [10,20,30,40,50]

print(a)

[10, 20, 30, 40, 50]

In [9]: #List of only strings

b = [ 'Sun', 'Mon', 'Tue', 'wed']

print(b)

['Sun', 'Mon', 'Tue', 'Wed']

In [10]: #List of both integers and string

c = [11, 'Red', 'Green',2,3, 'Blue']

print(c)

[11, 'Red', 'Green', 2, 3, 'Blue']

4) Tuple:

■ Tuple is a collection of elements and it is similar to the list. But the items of the tuple are separated by comma and the elements are enclosed in () parenthesis.

■ Tuples are immutable or read‒only. That means we can not modify the size of the tuple or we cannot change the value of items of the tuple.

■ Here are examples of tuples

In [1]: #Tuple of only integers

a = (10,20,30,40,50)

print(a)

(10, 20, 30, 40, 50)

In [2]: #Tuple of both integers and strings

 b = ('one',1,2, 'two', 'three',3)

print(b)

('one', 1, 2, 'two', 'three', 3)

We can display specific elements of a tuple using the index. For instance ‒

In [3]: print(b[3])

two

5) Dictionary:

■ Dictionary is a collection of elements in the form of key:value pair.

■ The elements of dictionary are present in the curly brackets.

■ For example ‒

In [4]: a = {1: 'Red',2: 'Blue',3: 'Green'}

 print(a)

{1: 'Red', 2: 'Blue', 3: 'Green'}

1. Boolean Values

There are two types of boolean values ‒ true or false.

The boolean expression can be represented using the operator. For example ‒

3= =3

True

3= =5

False

We can also check the data type of True and False with the help of type function.

type(True)

<class 'bool'>

type(False)

<class 'bool'>

Some of the valid boolean expressions are:

True

True

5= =4

False

3+2= =5

True