python - How to change index dtype of pandas DataFrame to int32?

Question

A default dtype of DataFrame index is int64 and I would like to change it to int32.

I tried changing it with pd.DataFrame.set_index and NumPy array of int32, also tried making new index with dtype=np.int32. It didn't work, always returning index of int64.

Can someone show a working code to produce Pandas index with int32 size?

I use conda Pandas v0.20.1.

Answer 1

Not sure this is something worth doing in practice, but the following should work:

class Int32Index(pd.Int64Index):
    _default_dtype = np.int32

    @property
    def asi8(self):
        return self.values

i = Int32Index(np.array([...], dtype='int32'))

(from here)