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Mutable Immutable ​

Mutability refers to whether an object's value can be changed after it's created. Immutable objects are those whose values cannot be changed once they are created. Immutable Objects are of in-built datatypes like int, float, bool, string, Unicode, and tuple.

Immutable Code Example ​

Integers

py
x = 5
y = x
y = 10  # This creates a new integer object with the value 10, x remains unchanged

String

py
s1 = "hello"
s2 = s1
s2 = "world"  # This creates a new string object "world", s1 remains unchanged

Tuple

py
tup1 = (1, 2, 3)
tup2 = tup1
# You cannot modify elements of a tuple after creation

Mutable Code Example ​

List

py
list1 = [1, 2, 3]
list2 = list1
list2.append(4)  # This modifies the list1 as well, since lists are mutable

Dictionaries

py
dict1 = {'a': 1, 'b': 2}
dict2 = dict1
dict2['c'] = 3  # This modifies the dict1 as well, since dictionaries are mutable

Sets

py
set1 = {1, 2, 3}
set2 = set1
set2.add(4)  # This modifies the set1 as well, since sets are mutable

Lists within Lists (Nested Lists):

py
nested_list1 = [[1, 2], [3, 4]]
nested_list2 = nested_list1
nested_list2[0][0] = 5  # This modifies the nested_list1 as well

Keep in mind that even if an object is mutable, assignment of the object to a new variable creates a reference to the same object rather than a new copy of it. So modifying the object through one reference will affect all references to that object. Immutable objects, on the other hand, don't suffer from this behavior because their values can't be changed.

Referemces: ​