Python data types



The following is the standard or built-in Python data type:

numeric

In Python, a numeric data type represents data that has a numeric value. The numeric value can be an integer, floating number, or even a complex number. These values ​​are defined in Python as int , float , and complex class.

  • Intergers — this value is represented by the int class. It contains positive or negative integers (no fractional or decimal). There is no limit to the length of the interger in Python.
  • Float — this value is represented by the float class. This is a real floating point number. Indicated by a decimal point. Optionally, the character e or E followed by a positive or negative integer can be added to indicate scientific notation.
  • Complex numbers — A complex number is represented by a complex class. Specified as (real) + (imaginary) j . For example — 2 + 3j

Note. The type () function is used to define the data type.

# Python program for
# show numeric value

 

a = 5

print ( "Type of a:" , type (a))

 

b = 5.0

print ( " Type of b: " , type (b))

 

c = 2 + 4j

print ( "Type of c:" , type (c ))

Output:

 Type of a: & lt; class `int` & gt; Type of b: & lt; class `float` & gt; Type of c: & lt; class `complex` & gt; 

Sequence type

In Python, the sequence — it is an ordered collection of similar or different data types. Sequences allow you to store multiple values ​​in an organized and efficient manner. There are several types of sequences in Python:

1) String

In Python, strings — they are arrays of bytes representing Unicode characters. The string — it is a set of one or more characters, enclosed in single, double, or triple quotes. There is no character data type in python, character is a string of length one. It is represented by the str class.

Creating a string

Strings in Python can be created using single or double quotes or even triple quotes.

# Python program for
# Create a line

 
# Create line
# with single quotes

String1 = `Welcome to the Geeks World`

print ( " String with the use of Single Quotes: "

print (String1) 

 
# Create a line
# with double quotes

String1 = "I`ma Geek"

print ( "String with the use of Double Quotes:"

print (String1) 

print ( type (String1))

  
# Create a line
# with triple quotes

String1 = "I am a geek and I live in a geek world

print ( "String with the use of Triple Quotes:"

print (String1) 

print ( type (String1))

  
# Create a triple line
# Quotes allow multiple lines

String1 = & # 39; & # 39; & # 39; Geeks

For

Life ""

print ( "Creating a multiline String:"

print (String1) 

Exit :

 String with the use of Single Quotes: Welcome to the Geeks World String with the use of Double Quotes: I `ma Geek & lt; class` str` & gt; String with the use of Triple Quotes: I`ma Geek and I live in a world of "Geeks" & lt; class `str` & gt; Creating a multiline String: Geeks For Life 

Accessing string elements

In Python, individual characters in a string can be accessed with using the indexing method. Indexing allows negative address references to access characters at the end of a line, for example, -1 refers to the last character, -2 refers to the second last character, and so on.
Raises IndexError when accessing an index out of range. Only integers are allowed, since index, floating point, or other types will cause TypeError .

# Python program for access
# line characters

 

String1 = "GeeksForGeeks"

print ( "Initial String:"

print (String1) 

 
# Print the first o character

print ( "First character of String is: "

print (String1 [ 0 ]) 

 
# Print the last character

print ( " Last character of String is: "

print (String1 [ - 1 ]) 

Output:

 Initial String: GeeksForGeeks First character of String is: G Last character of String is: s 

Remove / Update from Strings

In Python, updating or removing characters from a string is not allowed. This will throw an error because assigning an element or removing an element from a string is not supported. This is because strings are immutable, so the elements of a string cannot be changed once assigned. Only newlines can be reassigned to the same name.

# Python program to update / remove
# line character

 

String1 = "Hello, I`ma Geek"

print ( "Initial String:"

print (String1) 

 
# Character update
# lines

String1 [ 2 ] = `p`

print ( "Updating character at 2nd Index: "

print (String1) 

 
# Deleting a character
# lines

del String1 [ 2

print ( "Deleting character at 2nd Index:"

print (String1) 

Exit :

 Traceback (most recent call last): File “/home/360bb1830c83a918fc78aa8979195653.py”, line 10, in String1 [2] = `p `TypeError:` str `object does not s upport item assignment Traceback (most recent call last): File “/home/499e96a61e19944e7e45b7a6e1276742.py”, line 10, in del String1 [2] TypeError: `str` object doesn`t support item deletion 

Escape Sequencing in Python

When printing single and double quoted strings, it raises a SyntaxError because the string already contains single and double quotes and therefore does not can be printed using any of them. Hence, either triple quotes are used to print such a string, or Escape sequences are used to print such strings.
Escape sequences start with a backslash and can be interpreted in different ways. If single quotes are used to represent a string, then all single quotes present in the string must be escaped, and the same is done for double quotes.

# Program Python for
# Escape Sequencing
Line #

 
# Starting line

String1 = & # 39; & # 39; I`m & # 39; Geek & # 39; & # 39; & # 39; & # 39;

print ( " Initial String with use of Triple Quotes: "

print (String1) 

 
# Escaping one quote

String1 = `I`ma" Geek "`

print ( "Escaping Single Quote: "

print (String1) 

 
# Avoiding double quotes

String1 = "I`ma" Geek ""

print ( " Escaping Double Quotes: "

print (String1) 

 
# Print paths with
# use escape sequences

String1 = "C: Python Geeks "

print ( "Escaping Backslashes:"

print (String1) 

Exit:

 Initial String with use of Triple Quotes: I`ma " Geek "Escaping Single Quote: I`ma" Geek "Escaping Double Quotes: I`ma" Geek "Escaping Backslashes: C: PythonGeeks 

Note. To to learn more about strings,

# Python program for demonstration
# Create a list

 
# Create a list

List = [] 

print ( "Intial blank List:"

print ( List

  
# Create a list with
# use a string

List = [ `GeeksForGeeks`

print ( "List with the use of String: "

print ( List

  
# Create a list with
# use multiple values ​​

List = [ "Geeks" , "For" , "Geeks"

print ( "List containi ng multiple values: "

print ( List [ 0 ]) 

print ( List [ 2 ]) 

 
# Create a multidimensional list
# (Attaching a list to the list)

List = [[ `Geeks` , ` For` ], [ `Geeks` ]] 

print ( "Multi-Dimensional List:"

print ( List

Exit :

 Intial blank List: [] List with the use of String: [`GeeksForGeeks`] List containing multiple values: Geeks Geeks Multi-Dimensional List : [[`Geeks`,` For`], [`Geeks`]] 

Adding items to the list

Items can be added to the list using the append () built-in function. Only one element at a time can be added to the list using the append () method. To add an element to the desired position, use the insert () method. Besides the append () and insert () methods, there is another method for adding elements, extend () , this method is used to add multiple elements to the end of the list.

# Python program to demonstrate
# Add items to the list

 
# Create a list

List = [] 

print ( "Initial blank List:"

print ( List

 
# Adding elements
# in the list

List . append ( 1

List . append ( 2

List . append ( 4

print ( "List after Addition of Three elements:"

print ( List

 
# Add an element to
# specific position
# (using the insert method)

List . insert ( 3 , 12

List . insert ( 0 , `Geeks`

print ( "List after performing Insert Operation:"

print ( List

 
# Adding multiple elements
# to the end of the list
# (using the Extend method)

L ist . extend ([ 8 , `Geeks` , ` Always` ]) 

print ( "List after performing Extend Operation: "

print ( List

Exit :

 Initial blank List: [] List after Addition of Three elements: [1, 2, 4] List after Insert Operation: [`Geeks`, 1, 2, 4, 12] List after performing Extend Operation: [` Geeks`, 1, 2, 4, 12, 8, `Geeks`,` Always`]  

Accessing items from a list

To access items from a list, refer to the index number. Use the index operator [] to access an item in the list. The index must be an integer. The nested list is accessed using nested indexing. In Python, reverse sequence indices represent positions from the end of an array. Instead of calculating the offset, as in List [len (List) -3] , simply write List [-3] . Negative indexing means start at the end, -1 refers to the last item, -2 refers to the second last item, etc.

# Python program for demonstration
# access an item from the list

 
# Create a list with
# use multiple values ​​

List = [ "Geeks" , "For" , "Geeks"

 
# access to element from
# list by number py index

print ( "Accessing element from the list "

print ( List [ 0 ]) 

print ( List [ 2 ]) 

 
# access the element using
# negative indexing

print ( "Accessing element using negative indexing "

  
# print last list item

print ( List [ - 1 ]) 

 
# print the third last item in the list

print ( List [ - 3 ]) 

Exit:

 Accessing element from the list Geeks Geeks Accessing element using negative indexing Geeks Geeks 

Removing items from the list

Items can be removed from the list with using the built-in remove () function but an error occurs if the element does not exist in the set. The Pop () function can also be used to remove and return an item from a set, but by default it only removes the last item in the set, to remove an item from a specific position in the list, the item index is passed as an argument to the pop () method.

Note: The Remove method in the List will only remove the first occurrence of the item you are looking for.

# Python demo
# Remove items in the list

  
# Create a list

List = [ 1 , 2 , 3 , 4 , 5 , 6

                                                                                                                                                                                                                  7 , 8 , 9 , 10 , 11 , 12

print ( "Intial List:"

print ( List

 
# Removing items from the list
# using the Remove () method

List . remove ( 5

List .remove ( 6

print ( "List after Removal of two elements:"

print