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2009-8-16
磁针石:xurongzhong#gmail.com
博客:
oychw.cublog.cn
字符串转换为列表
>>> list('Hello')
['H', 'e', 'l', 'l', 'o']
列表转换为字符串
''.join(somelist)
基本的列表操作:
列表的赋值类似C语言中的数组操作。
删除元素:
>>> names = ['Alice', 'Beth',
'Cecil', 'Dee-Dee', 'Earl']
>>> del names[2]
>>> names
['Alice', 'Beth', 'Dee-Dee', 'Earl']
批量操作:
>>> name = list('Perl')
>>> name
['P', 'e', 'r', 'l']
>>> name[2:] = list('ar')
>>> name
['P', 'e', 'a', 'r']
>>> name = list('Perl')
>>> name[1:] = list('ython')
>>> name
['P', 'y', 't', 'h', 'o', 'n']
可以插入元素:
>>>
numbers = [1, 5]
>>> numbers[1:1] = [2, 3, 4]
>>> numbers
[1, 2, 3, 4, 5]
删除元素:
>>> numbers
[1, 2, 3, 4, 5]
>>> numbers[1:4] = []
>>> numbers
[1, 5]
列表的方法:
附加:
>>> lst = [1, 2, 3]
>>> lst.append(4)
>>> lst
[1, 2, 3, 4]
统计:
>>> ['to', 'be', 'or',
'not', 'to', 'be'].count('to')
2
>>> x = [[1, 2], 1, 1, [2,
1, [1, 2]]]
>>> x.count(1)
2
>>> x.count([1, 2])
1
扩展:
>>> a = [1, 2, 3]
>>> b = [4, 5, 6]
>>> a.extend(b)
>>> a
[1, 2, 3, 4, 5, 6]
与连接类似,不过连接返回的是新列表。
索引:
>>> knights = ['We', 'are',
'the', 'knights', 'who', 'say', 'ni']
>>> knights.index('who')
4
插入:
>>> numbers = [1, 2, 3, 5,
6, 7]
>>> numbers.insert(3,
'four')
>>> numbers
[1, 2, 3, 'four', 5, 6, 7]
出栈;
>>> x = [1, 2, 3]
>>> x.pop()
3
>>> x
[1, 2]
>>> x.pop(0)
1
>>> x
[2]
移除:
>>> x = ['to', 'be', 'or',
'not', 'to', 'be']
>>> x.remove('be')
>>> x
['to', 'or', 'not', 'to', 'be']
只移除第一次碰到的,无返回值。
翻转:
>>> x = [1, 2, 3]
>>> x.reverse()
>>> x
[3, 2, 1]
修改实际列表,无返回值。reversed是有返回值的。
排序:
>>> x = [4, 6, 2, 1, 7, 9]
>>> x.sort()
>>> x
[1, 2, 4, 6, 7, 9]
无返回值
>>> x = [4, 6, 2, 1, 7, 9]
>>> y = x[:]
>>> y.sort()
>>> x
[4, 6, 2, 1, 7, 9]
>>> y
[1, 2, 4, 6, 7, 9]
注意不要使用,这样指向的是同一个列表。
函数sorted是有返回值的。
高级排序:
内置函数cmp
>>> cmp(42, 32)
1
>>> cmp(99, 100)
-1
>>> cmp(10, 10)
0
>>> numbers = [5, 2, 9, 7]
>>> numbers.sort(cmp)
>>> numbers
[2, 5, 7, 9]
>>> x = ['aardvark',
'abalone', 'acme', 'add', 'aerate']
>>> x.sort(key=len)
>>> x
['add', 'acme', 'aerate', 'abalone',
'aardvark']
>>> x = [4, 6, 2, 1, 7, 9]
>>> x.sort(reverse=True)
>>> x
[9, 7, 6, 4, 2, 1]
更多参考:
http://wiki.python.org/moin/HowTo/Sorting
§2.4 数组
>>> 1, 2, 3
(1, 2, 3)
是不能修改的列表
以下第一个不是数组:
>>> 42
42
>>> 42,
(42,)
>>> (42,)
(42,)
>>> 3*(40+2)
126
>>> 3*(40+2,)
(42, 42, 42)
函数:
>>> tuple([1, 2, 3])
(1, 2, 3)
>>> tuple('abc')
('a', 'b', 'c')
>>> tuple((1, 2, 3))
(1, 2, 3)
基本操作:
>>> x = 1, 2, 3
>>> x[1]
2
>>> x[0:2]
(1, 2)
多用于key映射
本文来自ChinaUnix博客,如果查看原文请点:http://blog.chinaunix.net/u/21908/showart_2029141.html |
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