Beginners Guide To Data Types In Python

Data types are the classification or categorization of data items. It represents the kind of value that tells what operations can be performed on a particular data. Since everything is an object in Python programming, data types are actually classes and variables are instances (object) of these classes.

In this blog, we are going to look at the built-in data types available in Python like integer, string, and data structures like lists, tuples, etc.

What is a Data Type?

A data type or simply a type is a property of data, that tells the language processor (compiler, interpreter) how we are going to use this data.

• Data types tell the meaning of data, how that data is going to store in memory and what different operations can be performed on it.
• In the Python programming language, if we have to store any value in a variable, then the data type role comes into play.
• When we are storing a value in a variable, we have to use the same types of data as the type of variable. Each value belongs to some data type in Python.
• Data type identifies the type of data which a variable can hold and the operations that can be performed on those data.

Built-in Data Types

Following are the standard or built-in data types of Python:

• Numeric
• Sequence Type
• Boolean
• Set
• Dictionary

Further, these data types are divided into 2 specific categories: Mutable & Immutable.

Mutable Data Types

Data types in python where the value assigned to a variable can be changed are called mutable data types. In python we have the following mutable data types:

• Lists
• Sets
• Dictionaries

Immutable Data Types

Data types in python where the value assigned to a variable cannot be changed are called immutable data types. In python we have the following options:

• Numbers
• Tuples
• String

So let’s discuss each of these in detail and look at a few examples!

1.) Numeric Data Types

The numerical data type holds numerical value. In numerical data, there are 3 sub-types which are as follows:

1. Integers
2. Float
3. Complex Numbers

1.1 Integers

• Integers are used to represent whole number values like 0, 243, 124859, etc.
• They do not have any fraction parts. In Python, they are represented by numeric values with no decimal point.
• They can be positive or negative. Positive numbers are represented with a + (plus) sign, and negative numbers are represented by the – (minus) sign.
• Integers in Python 3.x can be of any length, it is limited by the memory available. Python provides a single data type integer to store an integer, whether big or small.
• This value is represented by int class.

##var1 is an integer variable

var1=21
type(var1)

1.2 Float

To declare the variables in a program that are to be used to stores decimal numbers, floating data type is used.

• The float data type is used to represent decimal point values.
• These numbers can be positive or negative.
• Floating points variables represent real numbers that are used for measurable quantities like distance, area, temperature, etc., and typically have a fractional part.
• Floating numbers represent machine-level double precision floating point numbers (15 digit precision).
• They are slower than integer operations.

##var2 is a floating type variable

var2 = 5.75
type(var2)

1.3 Complex Numbers

Complex numbers are used to represent imaginary values. Imaginary values are denoted with ‘j’ at the end of the number.

• A complex number is a composite quantity made of two parts -: the Real part and the Imaginary part. Both of which are represented internally as Float values (floating-point numbers).
• A complex number consists of both real and imaginary components.
• In complex numbers, A + Bj. where  A is a real number and B is an imaginary part. j is used for denoting the imaginary part.

##var3 is a complex data type variable

var3 = 6+5j
type(var3)

##output: <class 'complex'>

var3.real  ##output:6.0
var3.imag  ##output:5.0

Note: To check the type of any variable data type, we can use the type() function. It will return the type of the mentioned variable data type.

# Python program to 
# demonstrate numeric value
  
a = 5
print("Type of a: ", type(a))
  
b = 5.0
print("\nType of b: ", type(b))
  
c = 2 + 4j
print("\nType of c: ", type(c))

2.) Sequence Data Types

In Python, a sequence is the ordered collection of similar or different data types. Sequences allow storing multiple values in an organized and efficient fashion. There are several sequence types in Python –

• String
• List
• Tuple

2.1 String

When we provide information to the user, then the information is always represented as a group of characters, the group of characters is called String.

• A string is the Group of characters. These characters may be digits alphabets or special characters including spaces.
• A string data type lets you hold string data like any number, of valid characters into a set of quotation (” “)  marks.
• A string can hold any type of known character like letters, numbers, and special characters.

##str1, str2, str3 are string data type variables

##with double quotes
str1 = "Welcome to K21Academy"
print("String with the use of Double Quotes: ")
print(str1)  ##output: String with the use of Double Quotes: Welcome to K21Academy
type(str1)   ##output: <class 'str'> 

##with single quote
str2 = 'Hello World'
print("String with the use of Single Quotes: ")
print(str2)  ##output: String with the use of Single Quotes: hello World
type(str2)   ##output: <class 'str'> 

str3='12345'
type(str3)  ##output: <class 'str'>

2.2 List

# Python program to demonstrate Creation of List 

# Creating a List 
List = [] 
print("Initial blank List: ") 
print(List) 

# Creating a List with the use of a String 
List = ['K21Academy'] 
print("\nList with the use of String: ") 
print(List) 

# Creating a Multi-Dimensional List (By Nesting a list inside a List) 
List = [['K21Academy', 'For'], ['Cloud Computing']] 
print("\nMulti-Dimensional List: ") 
print(List)

#creating tuples

thistuple = ("apple", "banana", "cherry")
print(thistuple)

# Creating a Tuple with nested tuples 
Tuple1 = (0, 1, 2, 3) 
Tuple2 = ('apple', 'banana') 
Tuple3 = (Tuple1, Tuple2) 
print("\nTuple with nested tuples: ") 
print(Tuple3)

##var1 & var2 are boolean variables

var1 = True
type(var1)

var2 = False
type(var2)

##Example

print(10 > 9)
print(10 == 9)
print(10 < 9)

#create sets
thisset = {"apple", "banana", "cherry"}
print(thisset)

#duplicate values will be ignored
thisset = {"pencil", "pen", "eraser", "book", "pencil"}
print(thisset)

#length of set
thisset = {"pencil", "pen", "eraser", "book"}
print(len(thisset))

#working with dictionary
thisdict = {
  "brand": "Audi",
  "model": "A3",
  "year": 2014
}
print(thisdict)