Why are strings in Python immutable?
An immutable object is one that, once created, will not change in its lifetime.
Example
Try the following code to execute:
You will get an error message when you want to change the content of the string.
Solution
One possible solution is to create a new string object with necessary modifications:
name_1 = "Varun"name_2 = "T"+ name_1[1:]print("name_1 = ", name_1, "and name_2 = ", name_2)
To identify that they are different strings, check with the id() function:
name_1 = "Varun"name_2 = "T" + name_1[1:]print("id of name_1 = ", id(name_1))print("id of name_2 = ", id(name_2))
To understand more about the concept of string immutability, consider the following code:
name_1 = "Varun"name_2 = "Varun"print("id of name_1 = ", id(name_1))print("id of name_2 = ", id(name_2))
When the above lines of code are executed, you will find that the id’s of both name_1 and name_2 objects, which refer to the string “Varun”, are the same.
To dig deeper, execute the following statements:
name_1 = "Varun"print("id of name_1 = ", id(name_1))name_1 = "Tarun"print("id of name_1 afer initialing with new value = ", id(name_1))
As can be seen in the above example, when a string reference is reinitialized with a new value, it is creating a new object rather than overwriting the previous value.
In Python, strings are made immutable so that programmers cannot alter the contents of the object (even by mistake). This avoids unnecessary bugs.
Some other immutable objects are integer, float, tuple, and bool.
