Is There Any StringBuilder in Python?

Here we are going to see about there is any StringBuilder available in python. In C and Java programming, there is a StringBuilder. But we don’t have a built-in StringBuilder in Python. We can use string.join(), string concatenation, append, and string IO module to do this. The string builder in Java and C programming creates a mutable string and allows dynamic memory allocation.

A string is a collection of characters in Python. It is an immutable object that is an unchangeable string. We have to allocate new memory for every string. But using string builder, we can change the objects, so StringBuilder is mutable. In the latest versions of python, we are allowed to create a long string, and that is known as StringBuilder.

Difference between String and StringBuilder

StringStringBuilderIt is a collection of charactersIt is a collection of stringsIt is immutableIt is mutableThe new memory is allocated every timeAdded with existing string

4 Ways to Create a StringBuilder in Python

We can create a custom StringBuilder python using the below functions.

  • join() function
  • string concatenation
  • append
  • string IO module

1. Using join Function to Create StringBuilder in Python

1.1 Using join function without using loops to Create StringBuilder in Python

What is join() function?

join() is a built-in function in python that allows us to join multiple elements using a specific string. This function is much more simple to join the strings. If we want to join the strings without using this function, then this code will get longer. So using the join function will reduce the code length and makes the code legible.




iterable-required. Any iterable objects


combined string

a=["apple", "banana", "grapes"]

Here I have to print like apple is greater than banana and banana is greater than grapes. So I’m using the join function to join both the strings. First, I’m using variable a to hold the strings. Variable b holds the > symbol. At last, using the join function, both the strings are concatenated.



1.2 Using join function in loops to Create StringBuilder in Python

for i in range(3):

There is nothing different between using with loops and without loops. If we want to print one time, we can print without loops, but we can use for loop if we want to print multiple times.



2. Using String Concatenation to Create StringBuilder in Python

String concatenation means the joining of two or more strings is known as concatenation. The plus(+) operator is used to concatenate strings in python.


str1 + str2 +str3


srt1-first string, required str2-second string, required str3- third string, optional


concatenated string



First, I’m declaring str1 and str2. str1 contains some strings, and str2 also contains some strings. Now we have to join both the strings. For that, I’m using the + operator to concatenate the strings.



3. Using the append() Function to Create StringBuilder in Python

Adding more strings at the end of an existing string is known as append. It is a built-in function that is already available in the Python library. The operator += is used to append a new string with an existing string.




srt1-first string, required string=string to be added, required.


concatenated string


>>> str1="Welcome to "
>>> str1+="Python pool"
>>> print(str1)

First, the value of str1 is Welcome to. Now we have to add a Python pool on that string. So that we are using the append function to build the string. Now the string is concatenated.


Welcome to Python pool

4. Using the String IO module to Create StringBuilder in Python

This module is used to read and write strings. We can create a string IO object. getvalue() is useful to get the required string. We can use the string IO with class and without class.

4.1 Using without class

from io import StringIO
a = ['Hi ','this ','is ','Python']
string = StringIO()
for i in a:

First importing string IO module. Next to giving some string in a variable, a. Creating a for loop to iterate. Using getvalue() to get the required string.


Hi this is Python

4.2 Using class

from io import StringIO
class StringBuilder:
    string = None

    def __init__(self):
        self.string = StringIO()

    def Add(self, str):

    def __str__(self):
        return self.string.getvalue()
a=input("Enter your name: ")
string_builder = StringBuilder()
string_builder.Add("Welcome ")

First, importing a stringIO module. Next, create a class named StringBuilder. Initializing a string as None. Next to creating an input string to get the name from the user. Then gathering some strings together. Next using getvalue() to get the required string.


Enter your name: Priya
Welcome Mr/Ms/Mrs.Priya
1. Is string builder is available in python?

No, StringBuilder is not built-in in python. But, we can create a custom string builder.

2. What is StringBuilder?

String builder is a collection of strings. It is mutable and dynamic memory allocation.

3. How can we create a StringBuilder in python?

Use built-in functions like append(), string IO module, join(), and string concatenation.


Here we have seen StringBuilder in python. It is used to develop an existing string. StringBuilder is not readily available in python like C and Java. We have to create a custom StringBuilder in Python.

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