Python编程特殊小技巧汇集（一）

a = 0
b = 1
a,b = b, a

a, b = 2, 1

a,b,c,d = [1,3,4,'domi']
aa,*others = [1,3,4,'domi']
>>> others
[3, 4, 'domi']

a = 10
if 5<= a <= 15:
    print('Hello world')
    
 # 等价于
 if 5<= a and a <= 15:
    print('Hello world')

a = [1,'domi']*2
>>> a
[1, 'domi', 1, 'domi']

>>> a[1]*2
'domidomi'

a = 10
b = True if a==10 else False
>>> b
True
等价于
if a==10:
    b = True
else:
    b = False

a = {"a":1}
b = {"b":2}
>>> {**a, **b}
{'a': 1, 'b': 2}

s = "domi"
s1 = s[::-1]

s = ['d','o','m','i']
s1 = "".join(s)
>>> s1
'domi'

a = {x:x**2 for x in range(3)}
>>> a
{0: 0, 1: 1, 2: 4}

a_dict = {'a': 1, 'b': 2, 'c': 3}
{value:key for key, value in a_dict.items()}
{1: 'a', 2: 'b', 3: 'c'}

a = [1,2,3,3,0]
from collections import Counter
b = Counter(a)
b.most_common(1)
[(3, 2)]  # 3出现的次数最多，为2次

import re
s ="helloworld"
match = re.search('o', s)
if match:
    num = match.group(0)
else:
    num = None
num

if match := re.search('o', s):
    num = match.group(0)
else:
    num = None

a = 1.2
isinstance(a, (int, float))

b = "str"
isinstance(a, int)

s = "123asdz"
s.startswith("1")

s.endswith(("z","a"))

python3 -m http.server

a = [1,2,3,3,0]
max(set(a), key=a.count)

a.extend(['domi','+1'])
>>> a
[1, 2, 3, 3, 0, 'domi', '+1']

a[-2]
'domi'