Is a string a mutable or immutable data type? What is the essence of the division into mutable and immutable types? Name examples.

In most programming languages, a string is an immutable data type. This means that after creating a string, its contents cannot be changed — any operations that seem to modify the string actually create a new string.

The essence of mutable and immutable types:

• Mutable objects can be changed after creation, such as lists or dictionaries in Python.
• Immutable objects cannot be changed after creation, such as strings, tuples, numbers.

This division is important for data security, memory optimization, and multithreading. Immutable objects are easier to use as keys in dictionaries and are safe in concurrent access.

Examples:

• Immutable: strings, numbers (int, float), tuples
• Mutable: lists, dictionaries, sets

Python example:

s = "hello"
s2 = s.replace('h', 'j')  # creates a new string 'jello'
print(s)   # 'hello'
print(s2)  # 'jello'