[Python] Why the dotproduct using numpy arrays result in a different value than the manually...

I try to learn using Numpy in Python and tried following code and compared it to a manually written code. Both should reply the same dot product.

Here are the lines of code:

Python lists


arr1 = list(range(1000000))
arr2 = list(range(1000000, 2000000))


code

result = 0

for x1, x2 in zip(arr1, arr2):
result += x1 * x2
result


result 833332333333500000

Numpy arrays


arr1_np = np.array(arr1)
arr2_np = np.array(arr2)


code

np.dot(arr1_np, arr2_np)


result -1942957984`

I expected to get the same results as it was shown in a tutorial exactly the same way

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