# Python way (slow)
python_list = [1, 2, 3, 4, 5]
result = []
for x in python_list:
    result.append(x * 2)

# NumPy way (fast)
numpy_array = np.array([1, 2, 3, 4, 5])
result = numpy_array * 2  # [2 4 6 8 10]