Python字典：排序问题

Question

I thought i found away to sort a dictionary by clearing it then reassemble it in the order i wanted but for some reason it reorders itself the way it started out.

Here is the code if somebody can help me out

from operator import itemgetter

n = {}
d = {
 'a': ['2', 'ova', 'no'], 
 'b': ['23', 'movie', 'yes'], 
 'c': ['5', 'show', 'yes'], 
 'd': ['17', 'ova', 'yes'], 
 'e': ['1', 'movie', 'no']
}

for i in d:
    print i, d[i]

print '\n'

l = d.items()
l.sort(key=itemgetter(1)) #l is now sorted by the value of the string holding the integers
d.clear()

for i in l:
    print i[0], i[1]
    d[i[0]] = i[1] 

print '\n'

for i in d:
    print i, d[i] #Why does the dictionary come out to be the same it started from

Answer 1

字典本质上是无序的（因为它们使用哈希键-这是唯一的但任意的）[这是一个常见问题解答]-您可能要考虑使用OrderedDict （在2.7+版本中），它保留了插入顺序或PyPi的配方-否则，如果您需要订购，则需要按列表或其他顺序保留条目。

Answer 2

As Jon points out, dictionaries have no order. You get fast lookups by giving up ordering. You might not need it to keep an order though, since you have a sort order you like:

d = {'a':['2', 'ova', 'no'], 'b':['23', 'movie', 'yes'], 'c':['5', 'show', 'yes'], 'd':['17', 'ova', 'yes'], 'e':['1', 'movie', 'no']}
sorted_items = sorted(d.items(), key=itemgetter(1))
for i,v in sorted_items:
    print i, v