Creating Arrays, Shapes & Data Types

An array's dimensions are its levels of nesting:

• 0-D — a single value: np.array(42) • 1-D — a row of values: np.array([1, 2, 3]) • 2-D — rows and columns (a matrix): np.array([[1, 2, 3], [4, 5, 6]]) • 3-D — a stack of 2-D arrays, like an RGB image (height × width × 3 colors).

arr.ndim reports how many dimensions an array has. np.array([1, 2, 3], ndmin=3) forces extra dimensions.