分享一組 Python 高效編程的實(shí)用技巧

>>> a=3
>>> b=6

>>> a,b = b,a
>>> print(a)
>>> 6

>>> ptint(b)
>>> 5

>>>?some_list?=?[1,?2,?3,?4,?5]

>>>?another_list?=?[?x?+?1?for?x?in?some_list?]

>>>?another_list
[2,?3,?4,?5,?6]

>>>?#?Set?Comprehensions
>>>?some_list?=?[1,?2,?3,?4,?5,?2,?5,?1,?4,?8]

>>>?even_set?=?{?x?for?x?in?some_list?if?x?%?2?==?0?}

>>>?even_set
set([8,?2,?4])

>>>?#?Dict?Comprehensions

>>>?d?=?{?x:?x?%?2?==?0?for?x?in?range(1,?11)?}

>>>?d
{1:?False,?2:?True,?3:?False,?4:?True,?5:?False,?6:?True,?7:?False,?8:?True,?9:?False,?10:?True}

>>>?my_set?=?{1,?2,?1,?2,?3,?4}

>>>?my_set
set([1,?2,?3,?4])

>>>?from?collections?import?Counter
>>>?c?=?Counter('hello?world')

>>>?c
Counter({'l':?3,?'o':?2,?'?':?1,?'e':?1,?'d':?1,?'h':?1,?'r':?1,?'w':?1})

>>>?c.most_common(2)
[('l',?3),?('o',?2)]

>>>?import?json

>>>?print(json.dumps(data))??#?No?indention
{"status":?"OK",?"count":?2,?"results":?[{"age":?27,?"name":?"Oz",?"lactose_intolerant":?True},?{"age":?29,?"name":?"Joe",?"lactose_intolerant":?False}]}

>>>?print(json.dumps(data,?indent=2))??#?With?indention

{
??"status":?"OK",
??"count":?2,
??"results":?[

????{
??????"age":?27,
??????"name":?"Oz",

??????"lactose_intolerant":?true
????},
????{
??????"age":?29,

??????"name":?"Joe",
??????"lactose_intolerant":?false
????}
??]

}

for?x?in?range(1,101):
???print("fizz"[x%3*len('fizz')::]+"buzz"[x%5*len('buzz')::]?or?x)

>>>?print("Hello"?if?True?else?"World")
Hello

>>>?nfc?=?["Packers",?"49ers"]
>>>?afc?=?["Ravens",?"Patriots"]
>>>?print(nfc?+?afc)
['Packers',?'49ers',?'Ravens',?'Patriots']

>>>?print(str(1)?+?"?world")
1?world

>>>?print('1'?+?"?world")
1?world

>>>?print(1,?"world")
1?world
>>>?print(nfc,?1)
['Packers',?'49ers']?1

>>>?x?=?2
>>>?if?3?>?x?>?1:
... ???print(x)
2
>>>?if?1??0:
... ???print?x
2

>>>?nfc?=?["Packers",?"49ers"]
>>>?afc?=?["Ravens",?"Patriots"]
>>>?for?teama,?teamb?in?zip(nfc,?afc):
... ????print(teama?+?"?vs.?"?+?teamb)
Packers?vs.?Ravens
49ers?vs.?Patriots

>>>?teams?=?["Packers",?"49ers",?"Ravens",?"Patriots"]
>>>?for?index,?team?in?enumerate(teams):
...????print(index,?team)
0?Packers
1?49ers
2?Ravens
3?Patriots

numbers?=?[1,2,3,4,5,6]
even?=?[]
for?number?in?numbers:
????if?number%2?==?0:
????????even.append(number)

numbers?=?[1,2,3,4,5,6]
even?=?[number?for?number?in?numbers?if?number%2?==?0]

>>> teams?=?["Packers",?"49ers",?"Ravens",?"Patriots"]
>>> print({key:?value?for?value,?key?in?enumerate(teams)})
{'49ers':?1,?'Ravens':?2,?'Patriots':?3,?'Packers':?0}

>>> items?=?[0]*3
>>> print(items)
[0,0,0]

>>>?teams?=?["Packers",?"49ers",?"Ravens",?"Patriots"]
>>>?print(",?".join(teams))
'Packers,?49ers,?Ravens,?Patriots'

data?=?{'user':?1,?'name':?'Max',?'three':?4}
try:
???is_admin?=?data['admin']
except?KeyError:
???is_admin?=?False

data?=?{'user':?1,?'name':?'Max',?'three':?4}
is_admin?=?data.get('admin',?False)

>>> x?=?[1,2,3,4,5,6]
>>> print(x[:3]) #前3個(gè)
[1,2,3]

>>> print?x[1:5]  #中間4個(gè)
[2,3,4,5]

>>> print(x[3:]) #最后3個(gè)
[4,5,6]

>>> print(x[::2]) #奇數(shù)項(xiàng)
[1,3,5]

>>> print(x[1::2]) #偶數(shù)項(xiàng)
[2,4,6]

>>> from?itertools?import?combinations
>>> teams?=?["Packers",?"49ers",?"Ravens",?"Patriots"]
>>> for?game?in?combinations(teams,?2):
...????print(game)
('Packers',?'49ers')
('Packers',?'Ravens')
('Packers',?'Patriots')
('49ers',?'Ravens')
('49ers',?'Patriots')
('Ravens',?'Patriots')

False?=?True
if?False:
???print("Hello")
else:
???print("World")