arr = np.array([1, 2, 3, 4, 5, 6])

# Reshape to 2x3
reshaped = arr.reshape(2, 3)
print(reshaped)
# [[1 2 3]
#  [4 5 6]]

# Flatten back to 1D
flat = reshaped.flatten()  # [1 2 3 4 5 6]