String in Python

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String in Python is a collection of one or more characters . It can be surrounded by single quote , double quote , triple single quote or triple double quote . To create a multiline string we use triple single quote or triple double quote .

How to create a String in Python ?

There are multiple ways to create a string in Python –

Using single quote ('')
Using double quote ("")
Using triple single quote (''' ''')
Using triple double quote (""" """)
Using str() function

To check if it is a string or not we can use type() function .

Example 1:

# Creating a string in Python

# Using single quote ('')
single_quoted_string = 'coding conception'
# checking the type
print("type of single_quoted_string",type(single_quoted_string))

# using double quote ("")
double_quoted_string = "coding conception"
# checking the type
print("type of double_quoted_string",type(double_quoted_string))

# using triple single quote ('''''')
triple_single_string = '''coding conception'''
# checking the type
print("type of triple_single_string",type(triple_single_string))

# using triple double quote ("""""")
triple_double_string = """coding conception"""
# checking the type
print("type of triple_double_string",type(triple_double_string))

# using str function 
str_string = str(10)
# checking the type
print("type of str_string",type(str_string))

type of single_quoted_string <class 'str'>
type of double_quoted_string <class 'str'>
type of triple_single_string <class 'str'>
type of triple_double_string <class 'str'>
type of str_string <class 'str'>

In the above code we have seen how we can create a string using different way .

Note :

We use triple single quote or triple double quote only to create a multiline string otherwise we use single quote , double quote or str() function .

Example :

# multiline string

mul_string = '''I am Rajkumar Bhattacharya
             author at Codingconception.com'''
print(mul_string)

I am Rajkumar Bhattacharya
             author at Codingconception.com

How to access characters in a String in Python ?

We can access characters from a string using its index . So first we need to know about how indexing works in Python . For this reason we need to see the below image –

From the above image we can see that in Python index starts from 0 . So , index of first "C" from “Coding Conception” is 0 , index of first "o" from "Coding Conception" is 1 and so on . We can also see that length of "Coding Conception" is 17 but the last index number is 16 .

There is also one concept in Python that is negative indexing . Negative indexing in Python starts from -1 which points to the last element . We can see from the above image that -1 index points to the last character "n" of "Coding Conception" , -2 index points to the 2nd last character "o" of "Coding Conception" .

Example 1:

myString = "Coding Conception"

# Accessing first element
print("myString[0] =",myString[0])

# Accessing second element
print("myString[1] =",myString[1])

# Accessing last element
print("myString[len(myString)-1] =",myString[len(myString)-1])

myString[0] = C
myString[1] = o
myString[len(myString)-1] = n

In the above code first we have declared a string myString as "Coding Conception"
Then we have printed first character of the string by myString[0] that is C
After that we have printed second character of the string by myString[1] that is o
Then we have printed last character of the string by myString[len(myString)-1] that is n . As length of string is 17 so myString[len(myString)-1] treated as myString[16] .

Example 2:

myString = "Coding Conception"

# Accessing last element
print("myString[-1] =",myString[-1])

# Accessing second last element
print("myString[-2] =",myString[-2])

# Accessing first element
print("myString[-len(myString)] =",myString[-len(myString)])

myString[-1] = n
myString[-2] = o
myString[-len(myString)] = C

In the above code first we have declared a string myString as "Coding Conception"
Then we have printed last character of the string by myString[-1] that is n
After that we have printed second last character of the string by myString[-2] that is o
Then we have printed first character of the string by myString[-len(myString)] that is C . As length of string is 17 so myString[-len(myString] treated as myString[-17] .

Note :

If we give index outside the range then it will give IndexError .

myString = "Coding Conception"
print(myString[17])

---------------------------------------------------------------------------
IndexError                                Traceback (most recent call last)
C:\Users\RAJKUM~1\AppData\Local\Temp/ipykernel_9420/3574012407.py in <module>
      1 myString = "Coding Conception"
----> 2 print(myString[17])

IndexError: string index out of range

In the above code as the length of the string is 17 so index of last character will be (17-1)=16 . For this reason when we have given index as 17 Python has raised an IndexError .

Now , we have understood about indexing in Python . Now we will discuss about slicing of string in Python –

Slicing of String in Python

We can slice one or more character from a string using its index .

Syntax of Slicing

object[start : stop : step]

Parameters of Slicing

start = Optional , start specifies index number from where slicing will start . Default value is 0 .
Stop = Optional , stop specifies index number at where slicing will end but this number is excluded . Default value is (length of the object) .
step = Optional , An integer number which specifies the incrementation . Default is 1

Return type of Slicing

It returns a copy of the given datatype .

Example 1:

myString = "Coding Conception"

# if nothing is given 
# it will print the full string
print("myString[::] =",myString[::])

# slicing 2nd character to 4th character
print("myString[1:4] =",myString[1:4])
# as index of 4th character is 3 and stop 
# parameter is excluded so we need to give 
# stop parameter as 3+1=4

# if start parameter is not given
# then python will take it as 0
print("myString[:4] =",myString[:4])

# if stop parameter is not given
# then python will take it as len(myString)-1
print("myString[5:] =",myString[5:])

# if we want to print 1st ,3rd and 5th character
# then we need to give step parameter as 2
print("myString[0:5:2] =",myString[0:5:2])

# by default python takes step parameter as 1

myString[::] = Coding Conception
myString[1:4] = odi
myString[:4] = Codi
myString[5:] = g Conception
myString[0:5:2] = Cdn

In the above code we have seen various examples about slicing of string in Python

Example 2:

myString = "Coding Conception"

# slicing using negative indexing
# slicing 2nd last character to 4th last character
print("myString[-2:-5:-1] =",myString[-2:-5:-1])
# as index of 4th last character is -4 and stop 
# parameter is excluded so we need to give 
# stop parameter as -(4+1)=-5
# but to go -2 to -5 we need to give step as -1

# if we want to print last ,3rd last and 5th last character
# then we need to give step parameter as 2
print("myString[-1:-6:-2] =",myString[-1:-6:-2])

myString[-2:-5:-1] = oit
myString[-1:-6:-2] = nip

Note :

When we use negative step parameter then default value of start and stop parameter becomes -1 and -(length of the object) .

Example :

myString = "Coding Conception"

# when start and stop parameter both is not given
# python takes start and stop as -1 and -17
print("myString[::-1] =",myString[::-1])
# in this example we just reverse the string

# when stop parameter is not given python takes stop as -17
print("myString[5::-1] =",myString[5::-1])

# when start parameter is not given python takes start as -1
print("myString[:8:-1] =",myString[:8:-1])

myString[::-1] = noitpecnoC gnidoC
myString[5::-1] = gnidoC
myString[:8:-1] = noitpecn

How to update or delete a string in Python ?

In Python strings are immutable which means unchangeable . So , we can not change or update a string in Python . If we want to change a string using its index then it will raise a TypeError

Example 1:

myString = "Coding Conception"

# we want to change 2nd character "o" with "p"
myString[1]="p"

TypeError                                 Traceback (most recent call last)
C:\Users\RAJKUM~1\AppData\Local\Temp/ipykernel_5676/3264364102.py in <module>
      2 
      3 # we want to change 2nd character "o" with "p"
----> 4 myString[1]="p"

TypeError: 'str' object does not support item assignment

In the above code as we want to change myString using its index , it gave us a TypeError .

Example 2:

However , we can redeclare the same variable with other string . In that case program will not give any error –

myString = "Coding Conception"

# printing the string
print("myString =",myString)

# redeclaring the same variable with other string
myString="Rajkumar"

# printing the nrw string
print("myString =",myString)

myString = Coding Conception
myString = Rajkumar

In the above code by redeclaring the same variable we successfully change the string .

Example 3:

To delete a string we can use del keyword . But if we want to access the string after deleting it using del keyword it will raise a NameError .

myString = "Coding Conception"

# printing the string
print("myString =",myString)

# deleting the string
del myString

# printing the deleted string
# it will give error
print("myString =",myString)

myString = Coding Conception

---------------------------------------------------------------------------
NameError                                 Traceback (most recent call last)
C:\Users\RAJKUM~1\AppData\Local\Temp/ipykernel_5676/1461000573.py in <module>
      8 
      9 # printing the deleted string
---> 10 print("myString =",myString)

NameError: name 'myString' is not defined

In the above code after declaring the string we have printed the string successfully . But after deleting the string when we want to print the string it has raised a NameError .

Iterating a String in Python

We can iterate a string in Python using for-loop and while-loop .

Example 1:

# for loop with string as iterator
myString = "Rajkumar"
for letter in myString:
    print(letter)

R
a
j
k
u
m
a
r

In the above code we have iterated all character from myString using for-loop .

Example 2:

# python while loop with string datatype
name ="rajkumar"
number=0
while number < len(name):
    print(name[number])
    number+=1

r
a
j
k
u
m
a
r

In the above code we have iterated all character from myString using while-loop

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How to create a String in Python ?

Example 1:

Note :

Example :

How to access characters in a String in Python ?

Example 1:

Example 2:

Note :

Slicing of String in Python

Syntax of Slicing

Parameters of Slicing

Return type of Slicing

Example 1:

Example 2:

Note :

Example :

How to update or delete a string in Python ?

Example 1:

Example 2:

Example 3:

Iterating a String in Python

Example 1:

Example 2:

Like this:

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String in Python

How to create a String in Python ?

Example 1:

Note :

Example :

How to access characters in a String in Python ?

Example 1:

Example 2:

Note :

Slicing of String in Python

Syntax of Slicing

Parameters of Slicing

Return type of Slicing

Example 1:

Example 2:

Note :

Example :

How to update or delete a string in Python ?

Example 1:

Example 2:

Example 3:

Iterating a String in Python

Example 1:

Example 2:

Share this:

Like this:

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Leave a ReplyCancel reply