Definition

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In Python, a string is a sequence of characters enclosed or surrounded by single or double quotes. This sequence of UNICODE characters may be a letter, a number, special characters, or a back slash

Python doesn’t have any char datatype like C++ or java does.

In Python, a string can be denoted by enclosing it within single quotation marks or double quotation marks. Python treats both these quotes the same.

Example:

Creating string

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The string can be created by simply enclosing characters in quotation marks whether, it can be single, double or triple quotes.

Let us see the example how string is created:



In the above example,type function is used here to determine the object b value as string

Accessing String

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We can easily access all the elements of the string one after another by using the subscript and index value
Each character in a string has an index value. Indexing starts at 0 and must be an integer

Indexing can be performed either from left or right side.Left indexing starts from 0 and right indexing starts from -1.

Special String Operations

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Concatenating String

The + operator is used to join or concatenate two strings, written on both sides of the operator, and returns the new string after concatenating

Example:


You cannot concatenate a string object and an int object. To use the ‘+’ operator both the datatypes should be the same

Replicating String

The * operator replicates multiple copies of the same string depending on the number of repetitions inputted with * operator

Membership Operators

In python, we can also check whether a particular character exists in the given string or not using membership operators. These operators are ‘in’ and ‘not in’

'in’ operator: This operator returns true or false depending on whether the character or substring exists in a string

‘not in’ operator. This operator returns true when that specified character or substring does not exist in the given string

String slicing

String slicing as the name suggests is used to return the substring of the string. This extracted substring is termed a slice.

Here to extract the substring, we need to provide start index ,end index positions and the steps value which are separated by a colon(:) in the slice operator



We can also use the negative index to slice the string from the end of the string. In negative indexing, indexing starts from the right side

Basic String Operations

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Method	Description
len()	Returns length of the string
capitalize()	Returns given string with the first character in uppercase
split()	Breaks the string on the basis of the specified separator
replace()	Replace a string with another string
find()	Gives the index value of the specified string
index()	Returns the index of the character
isalpha()	Returns true if the string has only alphabets
isalnum()	Returns true if the string has both alphabets and numbers
isdigit()	Returns true if the string has only numbers
title()	capitalize the first letter of each word in a string
count()	Returns number of occurrences in the string
lower()	Returns a string in lower case characters
islower()	Returns true if the string has only lower case characters
upper()	Returns a string in uppercase characters
isupper()	Returns true if the string has only uppercase characters
lstrip()	Removes outerspace from left end of a string
rstrip()	Removes outerspace from right end of a string
strip()	Removes outerspace from both end of a string
isspace()	Returns true if the string has only whitespaces
istitle()	Returns true if the string is properly "titlecased"
swapcase()	Change lowercase characters to uppercase and vice versa
partition(seperator)	Breaks the string on the basis of the specified separator and returns tuple

len()

This method is used to return the length of the string
Syntax:

        len(str)
        

        str refers to string here
                        

Example:

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capitalize()

This method is used to convert the first character to uppercase of the given string
Syntax:

        str.capitalize()
        

        str refers to string here
                        

Example:

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split()

This method is used to break the string on the basis of the specified separator and returns a list of substring

Here if the separator is not specified, so by default, it assumes space as a separator
Syntax:

        str.split([seperator])
        

        str refers to string here
                        

Example:

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replace()

This method is used to replace all the occurrences of the old string with the new string
Syntax:

        str.replace(old,new)
        

        str refers to string here
        
        old refers to old string
        
        new refers to new string
                        

Example:

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find()

This method is used to find the first occurrence of the substring in the given string ,and returns its lowest index of the substring ,if it is not found then it returns -1

Here first parameter is the substring which needs to be searched in the given string

The second parameter is the starting position where substring is to be searched in the given string

And the third parameter refers to the last value for the specified range where substring is to be searched
Syntax:

        str.find(sub,start,end)
        

        str refers to string here
                        

Example:

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index()

This method is similar to find() method ,but it returns an error if that substring is not present in the given string
Syntax:

        str.index(substring,start,end)
        

        str refers to string here
                        

Example:

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isalpha()

This method is used to check whether the string contains only letters or not and returns a Boolean value i.e,true or false
Syntax:

        str.isalpha()
        

        str refers to string here
                        

Example:

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isalnum()

In this method, true is returned if all the characters are alphanumeric, which means alphabetic letters (a-z) and numbers (1-9)
Syntax:

        str.isalnum()
        

        str refers to string here
                        

Example:

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isdigit()

This method,returns true when the string contains only digits,otherwise false
Syntax:

        str.isdigit()
        

        str refers to string here
                        

Example:

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title()

This method is used to return the string with the first letter of every word in the string in uppercase and the rest in lowercase
Syntax:

        str.title()
        

        str refers to string here
                        

Example:

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count()

This method is used to return the number of times substring str occurs in the string.

If the start index and the end index are not specified the search starts from index 0 and ends with the length of the string
Syntax:

        str.count(substring,start,end)
        

        str refers to string here
                        

Example:

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lower()

This method is used to convert all the uppercase letters in the string into lowercase
Syntax:

        str.lower()
        

        str refers to string here
                        

Example:

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islower()

This method returns true if all the characters in the string are in lowercase
Syntax:

        str.islower()
        

        str refers to string here
                        

Example:

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upper()

This method is used to convert all the lowercase letters into uppercase letters in the string
Syntax:

        str.upper()
        

        str refers to string here
                        

Example:

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isupper()

This method returns true when all the characters in the string is in uppercase
Syntax:

        str.isupper()
        

        str refers to string here
                        

Example:

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lstrip()

This method returns string after removing extra space from the left side of the string
Syntax:

        str.lstrip()
        or
        str.lstrip(chars)
        

        str refers to string here
                        

Example:

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rstrip()

This method removes all the extra white spaces from the right of the string
Syntax:

        str.rstrip()
        or
        str.rstrip(chars)
        

        str refers to string here
                        

Example:

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strip()

This method returns string after removing extra spaces from both left and right side of the string
Syntax:

        str.strip()
        
        

        str refers to string here
                        

Example:

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isspace()

This method is used to check whether the string contains only whitespace characters or not
Syntax:

        str.isspace()
        
        

        str refers to string here
                        

Example:

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istitle()

This method is used to check whether the string is properly “titlecased” or not.It doesn’t take any arguments
Syntax:

        str.istitle()
        
        

        str refers to string here
                        

Example:

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swapcase()

This method is used to convert all uppercase letters to lowercase and lowercase to uppercase of the given string
Syntax:

        str.swapcase()
        
        

        str refers to string here
                        

Example:

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partition(seperator)

This method is used to divide or split the string using specified separator and returns a tuple with three parts:

• Substring after the separator
• Separator itself
• Substring before the seperator

Syntax:

        str.partition(seperator)
        
        

        str refers to string here
                        

Example:

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