>>> list=[]

>>> app=[list,list,list]

>>> app

[[], [], []]

>>> app[1].append(1)

>>> app

[[1], [1], [1]]

>>> id(app[1])

1666670423944

>>> id(app[2])

1666670423944

>>> app=[1,'',"cat",[]]

>>> for i in app:

	print(app[i])

>>> for i in app:

	print(i)

1

cat

[]

>>> for i in app:

	if i:

		print(i)

1

cat

>>> [i for i in app]

[1, '', 'cat', []]

>>> [i for i in app if i]

[1, 'cat']

>>> any(w!=0 for w in app)

True

>>> all(w!='' for w in app)

False

>>> t='ass',33,''

>>> t

('ass', 33, '')

>>> s

(2, 5, 3, 1, 6, 7, 95, 3)

>>> [n for n in s]

[2, 5, 3, 1, 6, 7, 95, 3]

>>> [n for n in sorted(s)]

[1, 2, 3, 3, 5, 6, 7, 95]

>>> [n for n in set(s)]

[1, 2, 3, 5, 6, 7, 95]

>>> [n for n in reversed(s)]

[3, 95, 7, 6, 1, 3, 5, 2]

>>> [n for n in s[::-1]]

[3, 95, 7, 6, 1, 3, 5, 2]

>>> [n for n in set(s).difference(t)]

[1, 2, 3, 5, 6, 7, 95]

>>> t=[1,23,4,5]

>>> [n for n in set(s).difference(t)]

[2, 3, 6, 7, 95]

>>> [n for n in random.shuffle(s)]

>>> text=open(r"C:\Users\BNC-PC\Desktop\text.txt","r").read()

>>> len(text)

34176

>>> cut=int(0.9*len(text))

>>> training_data,test_data=text[:cut],text[cut:]

>>> len(training_data)

30758

>>> len(test_data)

3418

>>> text == training_data + test_data

True

>>> len(training_data)/len(test_data)

8.998829724985372

>>>

>>> words='我 是 中国 人 ， 我 爱 祖国'.split()

>>> worelen=[w for w in words]

>>> worelen

['我', '是', '中国', '人', '，', '我', '爱', '祖国']

>>> '='.join(w for w in worelen)

'我=是=中国=人=，=我=爱=祖国'

def bncsum(m,n):

    sum=0

    if n:

        sum=m/n

    else:

        sum=n

    print(sum)

>>> bncsum(4,5)

0.8

>>> bncsum(4,0)

0

>>> help(bncsum)

Help on function bncsum in module __main__:

bncsum(m, n)