python pandas dataframe, is it pass-by-value or pass-by-reference

Question

If I pass a dataframe to a function and modify it inside the function, is it pass-by-value or pass-by-reference?

I run the following code

a = pd.Data         


        

Answer 1

Here is the doc for drop:

Return new object with labels in requested axis removed.

So a new dataframe is created. The original has not changed.

But as for all objects in python, the data frame is passed to the function by reference.