What is the difference between the parameters pass and ... when used inside a function?

In Python, pass and ... (ellipsis, also known as Ellipsis) have different purposes:

• pass is a placeholder statement that does nothing. It is used when the syntax requires a block body, but the logic is not yet implemented. For example:

def my_function():
    pass  # The function is empty for now

• ... (Ellipsis) is an object that can be used as a special value. In standard Python, it is rarely used, but it is often used in libraries (e.g., NumPy) to denote slices or missing parts. It can also be used as a placeholder, but it is not an operator, rather an object.

Example of using ... as a placeholder:

def my_function():
    ...  # Placeholder, similar to pass

Summary:

• pass — an operator that does nothing, used for correct syntax.
• ... — Ellipsis object, can be used as a placeholder or a special value in some contexts.