python之数据结构

List:

list.append(x)
list.extend(lis)
list.insert(i, x)
list.remove(x)
list.pop(i)
#会同时返回移除的值，如果没有设置i，则返回最后一个值
del list[i]   del list[i:j]
list.index(x)
#返回x第一次出现的位置
list.count(x)
#返回x出现的次数
list.sort()  #sorted()  见blog sort高级用法
list.reverse()

#list快速创建：
lis = [x**2 for x in range(10)]

[(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]
-----------------------------------
[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]

matrix = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
[[row[i] for row in matrix] for i in range(4)]
------------------------------------
[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]

zip:
>>> x = [1, 2, 3]
>>> y = [4, 5, 6]
>>> zipped = zip(x, y)
>>> zipped
[(1, 4), (2, 5), (3, 6)]
>>> x2, y2 = zip(*zipped)
>>> x == list(x2) and y == list(y2)
True

Dictionary：

>>> a = dict(one=1, two=2, three=3)
>>> b = {‘one‘: 1, ‘two‘: 2, ‘three‘: 3}
>>> c = dict(zip([‘one‘, ‘two‘, ‘three‘], [1, 2, 3]))
>>> d = dict([(‘two‘, 2), (‘one‘, 1), (‘three‘, 3)])
>>> e = dict({‘three‘: 3, ‘one‘: 1, ‘two‘: 2})
>>> a == b == c == d == e
True

del d[key]
dic.clear()   #Remove all items from the dictionary.
dic.copy()    #Return a shallow copy of the dictionary
dic.get(key[, default])   #f default is not given, it defaults to None
dic.pop(key[, default])   #If key is in the dictionary, remove it and return its value, else return default. If default is not given and key is not in the dictionary, a KeyError is raised.
dic.popitem()     #Remove and return an arbitrary (key, value) pair from the dictionary.
dic.items()    #Return a copy of the dictionary’s list of (key, value) pairs.
dic.keys()     #Return a copy of the dictionary’s list of keys
dic.values()   #eturn a copy of the dictionary’s list of values
dic.iteritems() dic.iterkeys() dic.itervalues()

set：

python的set和其他语言类似, 是一个无序不重复元素集。
基本功能包括关系测试和消除重复元素. 集合对象还支持union(合), intersection(交), difference(差)和sysmmetric difference(对称差集)等数学运算.  

sets 支持 x in set, len(set),和 for x in set。作为一个无序的集合，sets不记录元素位置或者插入点。因此，sets不支持 indexing, slicing, 或其它类序列（sequence-like）的操作。 

s = set([3,5,9,10])      #创建一个数值集合
t = set("Hello")         #创建一个唯一字符的集合
------------
set([‘H‘, ‘e‘, ‘l‘, ‘o‘])

a = t | s          # t 和 s的并集
b = t & s          # t 和 s的交集
c = t – s          # 求差集（项在t中，但不在s中）
d = t ^ s          # 对称差集（项在t或s中，但不会同时出现在二者中）

用set去除列表中重复元素
>>> [i for i in set([11,22,33,44,11,22])]
[33, 11, 44, 22]