列表转换成字典数据结构

'''
[
    {'symbol': 101, 'sort': 1, 'name': 'aaaa'},
    {'symbol': 102, 'sort': 2, 'name': 'bbbb'},
    {'symbol': 103, 'sort': 3, 'name': 'cccc'},
    {'symbol': 104, 'sort': 4, 'name': 'dddd'},
    {'symbol': 105, 'sort': 5, 'name': 'eeee'},
    {'symbol': 106, 'sort': 6, 'name': 'ffff'},
    {'symbol': 107, 'sort': 7, 'name': 'gggg'},
    {'symbol': 108, 'sort': 8, 'name': 'hhhh'},
    {'symbol': 109, 'sort': 9, 'name': 'iiii'}
]
转换成如下的结构，便于通过ID获取记录值
{
    101: {'sort': 1, 'symbol': 101, 'name': 'aaaa'},
    102: {'sort': 2, 'symbol': 102, 'name': 'bbbb'},
    103: {'sort': 3, 'symbol': 103, 'name': 'cccc'},
    104: {'sort': 4, 'symbol': 104, 'name': 'dddd'},
    105: {'sort': 5, 'symbol': 105, 'name': 'eeee'},
    106: {'sort': 6, 'symbol': 106, 'name': 'ffff'},
    107: {'sort': 7, 'symbol': 107, 'name': 'gggg'},
    108: {'sort': 8, 'symbol': 108, 'name': 'hhhh'},
    109: {'sort': 9, 'symbol': 109, 'name': 'iiii'}
}
'''
students = [
        {'symbol': 101, 'sort': 1, 'name': 'aaaa'},
        {'symbol': 102, 'sort': 2, 'name': 'bbbb'},
        {'symbol': 103, 'sort': 3, 'name': 'cccc'},
        {'symbol': 104, 'sort': 4, 'name': 'dddd'},
        {'symbol': 105, 'sort': 5, 'name': 'eeee'},
        {'symbol': 106, 'sort': 6, 'name': 'ffff'},
        {'symbol': 107, 'sort': 7, 'name': 'gggg'},
        {'symbol': 108, 'sort': 8, 'name': 'hhhh'},
        {'symbol': 109, 'sort': 9, 'name': 'iiii'}
    ]
 
symbol_list = map(lambda x: (x.get('symbol'), x), students)
print symbol_list
print '-----------------------------------------'
print dict(symbol_list)
#value_list = map(lambda x: x, students)
#
##print dict(zip(symbol_list, value_list))
#
#
#student = {
#        101: {'symbol': 101, 'sort': 1, 'name': 'aaaa'}
#        }
#
#student = [
#        {101: {'symbol': 101, 'sort': 1, 'name': 'aaaa'}}
#        ]
#


排序用法：
students = [
            {'name':'zhangsan', 'price':20.01, 'date':'2015-01-09T01:00:00Z'},
            {'name':'lisi', 'price':10.01, 'date':'2013-01-09T01:00:00Z'},
            {'name':'wangwu', 'price':0.01, 'date':'2012-01-09T01:00:00Z'}
]  

print sorted(students, key=lambda s:s["name"])
print sorted(students, key=lambda s:s["price"], reverse=True)
print sorted(students, key=lambda s:s["date"],  reverse=True)
aa = sorted(students, key=lambda s:s["price"], reverse=True)
sorted(aa, key=lambda s:s["date"],  reverse=True)

symbol_arr = [<Symbol: Symbol object>, <Symbol: Symbol object>, <Symbol: Symbol object>] 
sorted(symbol_arr, key=lambda s:s.amount, reverse=True)