pandas - How to make python object callable by numpy.array()

Some classes, such as Series in pandas produce instances that can be called by numpy.array and turned into numpy arrays.

How do I make instances of a class that I'm writing (which works with a few arrays at the core) be allowed to be passed as argument to numpy.array and converted to a numpy array?

(perhaps "callable" is not the right word)

Answer

It looks like one easy way is to make the object define an __array__(self) method that returns the array you want numpy.array to return.

You can also make your object a sequence: define __iter__(self) to return an iterator over all the items, __getitem__(self, i), to return the ith element, and and __len__(self) to return the length.