是否再次进行Numpy数组的原位类型转换？

Question

I have got an array of floats and I would like to cast it into int .

a1 = np.ones(10)
a2 = a1.astype(int, copy=False)
a2.dtype # int
a1.dtype # float

What's going on here? I thought astype(int, copy=False) would cast types in-places. But it doesn't appear to do so?

related question: In-place type conversion of a NumPy array

Answer 1

From the copy argument documentation :

If this is set to false, and the dtype, order, and subok requirements are satisfied, the input array is returned instead of a copy.

It can't actually convert the type in place. It only works if the input array is already of the dtype you want; otherwise, it has to make a copy anyway.