Why do numpy array turns int into float

问题

I'm trying to fill an array with integers, but it seems like numpy array keep turning the integers into floats. Why is this happening and how do I stop this?

arr = np.empty(9)
arr[3] = 7
print(arr[3])
>>>7.0

回答1:

NumPy arrays, unlike Python lists, can contain only a single type, which (as far as I know) is set at creation time. Everything you put into the array gets converted to that type.

By default, the data type is assumed to be float. To set another type, you can pass dtype to the empty function like this:

>>> arr = np.empty(9, dtype=int)
>>> arr[3] = 7
>>> arr[3]
7

来源：https://stackoverflow.com/questions/51607607/why-do-numpy-array-turns-int-into-float