为什么numpy数组将int转换为float

Question

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

Answer 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