求助！怎样理解字典的输出结果

hunsjie

代码：

# create a mapping of state to abbreviation
states = {
    'Oregon': 'OR',
    'Florida': 'FL',
    'California': 'CA',
    'New York': 'NY',
    'Michigan': 'MI'
}

# print every state abbreviation
print '-' * 10
for state, abbrev in states.items():
    print "%s is abbreviated %s" % (state, abbrev)

结果：
California is abbreviated CAMichigan is abbreviated MINew York is abbreviated NYFlorida is abbreviated FLOregon is abbreviated OR

为何输出的顺序并不是按字典顺序呢？还是输出有某个规则？

crossin先生

字典是无序的，这点和list是不一样的。所以字典也不能直接用索引访问，只能通过key来访问