How do you determine if a data type's value can be changed after its declaration?

In Python, data types can be divided into mutable and immutable. Mutable objects can be changed after creation, while immutable ones cannot.

Examples:

• Mutable: lists (list), dictionaries (dict), sets (set)
• Immutable: numbers (int, float), strings (str), tuples (tuple)

To determine if a value can be changed, you need to know the object's type. For example, a list can be modified:

lst = [1, 2, 3]
lst[0] = 10  # change the first element

But a string cannot be changed directly:

s = "hello"
# s[0] = 'H'  # will cause an error

Thus, mutability depends on the data type, not on the variable declaration.