1. import numpy as np
    3. if __name__ == "__main__":
    5.     z = [1,2,3,4,5]
    6.     print(len(z))  # 5
    8.     x = [[1,2,3], [1, 2, 3], [1,2,3], [4,5,6]]
    9.     print(len(x))  # 4
    11.     y = []
    12.     y.append(np.ones((11, 768)))
    13.     y.append(np.ones((14, 768)))
    14.     y.append(np.ones((5, 768)))
    16.     for i in y:
    17.         print(len(i))  # 11   14    5