In [1]:

    

l = [0, 1, 2, 3]

print(len(l))


    

    




4

In [2]:

    

l_length = len(l)


    

In [3]:

    

print(l_length)


    

    




4

In [4]:

    

print(type(l_length))


    

    




<class 'int'>

In [5]:

    

l_2d = [[0, 1, 2], [3, 4, 5]]

print(len(l_2d))


    

    




2

In [6]:

    

print([len(v) for v in l_2d])


    

    




[3, 3]

In [7]:

    

print(sum(len(v) for v in l_2d))


    

    




6

In [8]:

    

import numpy as np


    

In [9]:

    

l_2d = [[0, 1, 2], [3, 4, 5]]
arr_2d = np.array(l_2d)

print(arr_2d)


    

    




[[0 1 2]
 [3 4 5]]

In [10]:

    

print(arr_2d.size)


    

    




6

In [11]:

    

print(arr_2d.shape)


    

    




(2, 3)

In [12]:

    

l_multi = [[0, 1, 2, [10, 20, 30]], [3, 4, 5], 100]

print(len(l_multi))


    

    




3

In [13]:

    

arr_multi = np.array(l_multi)
print(arr_multi)


    

    




[list([0, 1, 2, [10, 20, 30]]) list([3, 4, 5]) 100]

In [14]:

    

print(arr_multi.size)


    

    




3

In [15]:

    

print(arr_multi.shape)


    

    




(3,)

In [16]:

    

def my_len(l):
    count = 0
    if isinstance(l, list):
        for v in l:
            count += my_len(v)
        return count
    else:
        return 1


    

In [17]:

    

l_multi = [[0, 1, 2, [10, 20, 30]], [3, 4, 5], 100]
print(my_len(l_multi))


    

    




10

In [18]:

    

l_2d = [[0, 1, 2], [3, 4, 5]]
print(my_len(l_2d))


    

    




6

In [19]:

    

l = [0, 1, 2, 3]
print(my_len(l))


    

    




4