In [1]:

    

import numpy as np


    

In [2]:

    

l = [0, 1, 2]
print(type(l))


    

    




<class 'list'>

In [3]:

    

print(hasattr(l, 'append'))


    

    




True

In [4]:

    

print(hasattr(l, 'xxx'))


    

    




False

In [5]:

    

print(len(l))


    

    




3

In [6]:

    

print(l.__len__())


    

    




3

In [7]:

    

def print_len_hasattr(x):
    if hasattr(x, '__len__'):
        print(len(x))
    else:
        print('x has no __len__')


    

In [8]:

    

print_len_hasattr([0, 1, 2])


    

    




3

In [9]:

    

print_len_hasattr('abc')


    

    




3

In [10]:

    

print_len_hasattr(100)


    

    




x has no __len__

In [11]:

    

a = np.arange(3)
print(a)


    

    




[0 1 2]

In [12]:

    

print_len_hasattr(a)


    

    




3