What is Strings and How to Create, Index and Split in Python?

[vishrut-singhal]

Python String

Till now, we have discussed numbers as the standard data-types in Python. In this section of the tutorial, we will discuss the most popular data type in Python, i.e., string.

Python string is the collection of the characters surrounded by single quotes, double quotes, or triple quotes. The computer does not understand the characters; internally, it stores manipulated character as the combination of the 0’s and 1’s.

Each character is encoded in the ASCII or Unicode character. So we can say that Python strings are also called the collection of Unicode characters.

In Python, strings can be created by enclosing the character or the sequence of characters in the quotes. Python allows us to use single quotes, double quotes, or triple quotes to create the string.

Consider the following example in Python to create a string.

Syntax:

1. str = "Hi Python !"

Here, if we check the type of the variable str using a Python script

`print(type(str)), then it will print a string (str).`

In Python, strings are treated as the sequence of characters, which means that Python doesn’t support the character data-type; instead, a single character written as ‘p’ is treated as the string of length 1.

Creating String in Python

We can create a string by enclosing the characters in single-quotes or double- quotes. Python also provides triple-quotes to represent the string, but it is generally used for multiline string or docstrings .

>     #Using single quotes  

    str1 = 'Hello Python'  
    print(str1)  
    #Using double quotes  
    str2 = "Hello Python"  
    print(str2)  
      
    #Using triple quotes  
    str3 = '''''Triple quotes are generally used for  
        represent the multiline or 
        docstring'''   
    print(str3)  

Output:

Hello Python
Hello Python
Triple quotes are generally used for 
    represent the multiline or
    docstring

Strings indexing and splitting

Like other languages, the indexing of the Python strings starts from 0. For example, The string “HELLO” is indexed as given in the below figure.

Consider the following example:

str = "HELLO"  
print(str[0])  
print(str[1])  
print(str[2])  
print(str[3])  
print(str[4])  
# It returns the IndexError because 6th index doesn't exist  
print(str[6])  

Output:

H
E
L
L
O
IndexError: string index out of range

As shown in Python, the slice operator [] is used to access the individual characters of the string. However, we can use the : (colon) operator in Python to access the substring from the given string. Consider the following example.

Here, we must notice that the upper range given in the slice operator is always exclusive i.e., if str = ‘HELLO’ is given, then str[1:3] will always include str[1] = ‘E’, str[2] = ‘L’ and nothing else.

Consider the following example:

# Given String  
str = "JAVATPOINT"  
# Start Oth index to end  
print(str[0:])  
# Starts 1th index to 4th index  
print(str[1:5])  
# Starts 2nd index to 3rd index  
print(str[2:4])  
# Starts 0th to 2nd index  
print(str[:3])  
#Starts 4th to 6th index  
print(str[4:7])  

Output:

JAVATPOINT
AVAT
VA
JAV
TPO

We can do the negative slicing in the string; it starts from the rightmost character, which is indicated as -1. The second rightmost index indicates -2, and so on. Consider the following image.

Consider the following example

str = 'JAVATPOINT'  
print(str[-1])  
print(str[-3])  
print(str[-2:])  
print(str[-4:-1])  
print(str[-7:-2])  
# Reversing the given string  
print(str[::-1])  
print(str[-12]) 

Output:
T
I
NT
OIN
ATPOI
TNIOPTAVAJ
IndexError: string index out of range