python学习琐碎

使用 list() / tuple() 函数在列表和元组之间进行转换

 

>>>>>> a = ['a', 'b', 'c']
>>>>>> a
['a', 'b', 'c']
>>>>>> b = tuple(a)
>>>>>> b
('a', 'b', 'c')('a', 'b', 'c')
>>>>>> c = list(b)
>>>>>> c
['a', 'b', 'c']
>>>>>>

列表支持运算符操做

 

>>>>>> [1, 2] * 2
[1, 2, 1, 2]
>>>>>> [1, 2] + [3, 4]
[1, 2, 3, 4]
>>>>>>

 

能够使用 in / not in 来判断是否包含某个元素。

 

>>>>>> a = [1, 2, 3]
>>>>>> 1 in a
True
>>>>>> 4 in a
False
>>>>>> b = (1, 2, 3)
>>>>>> 2 in b
True
>>>>>>

使用 range() 函数得到一个整数列表，甚至进行运算和添加过滤条件

 

>>>>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>>>>> range(2, 10, 2)
[2, 4, 6, 8]
>>>>>> range(2, 7)
[2, 3, 4, 5, 6]
>>>>>> [x*2 for x in range(10)]
[0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
>>>>>> [x for x in range(10) if x%2>0]
[1, 3, 5, 7, 9]
>>>>>> [x + 1 for x in range(10) if x%2==0]
[1, 3, 5, 7, 9]
>>>>>>