Python语法小技巧

1.两个变量值互换

a = 1
b = 2
a, b = b, a
>>> a
2
>>> b
1

2.连续赋值

a = b = c = 20
>>> a
20
>>> b
20
>>> c
20

3.解包

a, b, c = [0, 1, 2]
>>> a
0
>>> b
1
>>> c
2

a, *others = [1, 2, 3, 4]
>>> a
1
>>> others
[2, 3, 4]

4.链式比较

a = 15
if （1 < a < 2):
    print("true")

5.重复列表

>>> [5, 2] * 3
[5, 2, 5, 2, 5, 2]

6.字典合并

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

7.字符串反转

>>> s = 'hello world'
>>> s[::-1]
'dlrow olleh'

8.列表转字符串

>>> s = ['hello', 'world']
>>> "".join(s)
'helloworld'

9.字典推导式

>>> m = {
     X: x**2 for x in range(5)}
>>> m
{
     0: 0, 1: 1, 2: 4, 3: 9, 4: 16}

10.拓展列表

>>> i = ['a', 'b', 'c']
>>> i.extend(['e', 'f', 'g'])
>>> i
['a', 'b', 'c', 'e', 'f', 'g']

11.列表负数索引

>>> a = [1, 2, 3]
>>> a[-1]
3

12.列表去重

list0 = [1, 2, 3, 2, 2, 5, 6, 5]
list0 = list(set(list0))
>>> list0
[1, 2, 3, 5, 6]