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:

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

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.

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:

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:

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

Output:

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

Reassigning Strings

Updating the content of the strings is as easy as assigning it to a new string. The string object doesn’t support item assignment i.e., A string can only be replaced with new string since its content cannot be partially replaced. Strings are immutable in Python.

Consider the following example.

Example 1

Output:

Traceback (most recent call last):
  File "12.py", line 2, in <module>
    str[0] = "h";
TypeError: 'str' object does not support item assignment

However, in example 1, the string str can be assigned completely to a new content as specified in the following example.

Example 2

Output:

HELLO
hello  

Deleting the String

As we know that strings are immutable. We cannot delete or remove the characters from the string.  But we can delete the entire string using the del keyword.

Output:

TypeError: 'str' object doesn't support item deletion

Now we are deleting entire string.

Output:

NameError: name 'str1' is not defined

String Operators

Example

Consider the following example to understand the real use of Python operators.

Output:

HelloHelloHello
Hello world
o
ll
False
False
C://python37
The string str : Hello

Python String Formatting

Escape Sequence

Let’s suppose we need to write the text as – They said, “Hello what’s going on?”- the given statement can be written in single quotes or double quotes but it will raise the SyntaxError as it contains both single and double-quotes.

Example

Consider the following example to understand the real use of Python operators.

Output:

SyntaxError: invalid syntax

We can use the triple quotes to accomplish this problem but Python provides the escape sequence.

The backslash(/) symbol denotes the escape sequence. The backslash can be followed by a special character and it interpreted differently. The single quotes inside the string must be escaped. We can apply the same as in the double quotes.

Example –

Output:

They said, "What's there?"
They said, "What's going on?"
They said, "What's going on?"

The list of an escape sequence is given below:

print("Python1 /
Python2 /
Python3")

Python1 Python2 Python3

print("//")

/

print('/'')

'

print("/"")

"

print("/a")

print("Hello /b World")

Hello World

print("Hello /f World!")
Hello  World!

print("Hello /n World!")

Hello
 World!

print("Hello /r World!")

World!

print("Hello /t World!")

Hello 	 World!

print("Hello /v World!")

Hello 
 World!

print("/110/145/154/154/157")
Output:
Hello

print("/x48/x65/x6c/x6c/x6f")

Hello

Here is the simple example of escape sequence.

Output:

C:/Users/DEVANSH SHARMA/Python32/Lib
This is the 
 multiline quotes
This is HEX representation

We can ignore the escape sequence from the given string by using the raw string. We can do this by writing r or R in front of the string. Consider the following example.

Output:

C://Users//DEVANSH SHARMA//Python32

The format() method

The format() method is the most flexible and useful method in formatting strings. The curly braces {} are used as the placeholder in the string and replaced by the format() method argument. Let's have a look at the given an example:

Output:

Devansh and Abhishek both are the best friend
Rohit and Virat best players 
James,Peter,Ricky 

Python String Formatting Using % Operator

Python allows us to use the format specifiers used in C's printf statement. The format specifiers in Python are treated in the same way as they are treated in C. However, Python provides an additional operator %, which is used as an interface between the format specifiers and their values. In other words, we can say that it binds the format specifiers to the values.

Consider the following example.

Output:

Hi I am Integer ... My value is 10
Hi I am float ... My value is 1.290000
Hi I am string ... My value is Devansh

Python String functions

Python provides various in-built functions that are used for string handling. Many String fun