A flat 1D array with 12 elements. Each box is color-coded by its original position.
NumPy
import numpy as np
arr = np.array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12])
print(arr.shape) # (12,)
print(arr.ndim) # 1
ML Use Case
A 1D array = one training sample. If a house has 12 features (size, rooms, age…), it is stored as a 1D array of shape (12,). Neural network input layers expect each sample in this format.