# >>> import numpy as np
# >>> x = np.array([1.0, 2.0, 3.0])
# >>> print(x)
# >>> type(x)
# >>> x = np.array([1.0, 2.0, 3.0])
# >>> y = np.array([2.0, 4.0, 6.0])
# >>> x + y
# >>> x - y
# >>> x / y
# >>> x = np.array([1.0, 2.0, 3.0])
# >>> x / 2.0
# >>> A = np.array([[1, 2], [3, 4]])
# >>> print(A)
# >>> A.shape
# >>> A.dtype
# >>> B = np.array([[3, 0], [0, 6]])
# >>> A + B
# >>> A * B
# >>> print(A)
# >>> A * 10
# >>> A = np.array([[1, 2], [3, 4]])
# >>> B = np.array([10, 20])
# >>> A * B
# >>> X = np.array([[51, 55], [14, 19], [0, 4]])
# >>> print(X)
# >>> X[0]
# >>> X[0][1]
# >>> for row in X:
# ...     print(row)
# ...
# >>> X = X.flatten()
# >>> print(X)
# >>> X[np.array([0, 2, 4])]
# >>> X > 15
# >>> X[X>15]