What are immutable default parameters in Python?

What are immutable default parameters in Python?

Immutable default parameters in Python are default values for function arguments that cannot be changed. Examples include tuples and strings.

Can you give me an example of how to use them?

Sure! Here's an example:

def my_function(param1, param2=[]):
    param2.append(param1)
    return param2

In this case, if you call my_function(1), it will modify the default list.

What issues can arise from using mutable default parameters?

Using mutable default parameters can lead to unexpected behavior, as the same object is shared across function calls. This can cause data to persist between calls.

How can I avoid these issues?

To avoid these issues, use None as a default value and create a new object inside the function:

def my_function(param1, param2=None):
    if param2 is None:
        param2 = []
    param2.append(param1)
    return param2