我有这个东西
mydict = OrderedDict({'a':'1', 'd':'2','f':'1', 'i':'2','m':'1', 'k':'2'})
现在假设我有像
这样的列表 l = [i,k]
所以我想根据列表l
订购mydict。这样i,k
将是前两个项目,然后其他项目保持原始顺序
我想尽可能少地编写代码。在Python中
答案 0 :(得分:5)
使用itertools中的unique_everseen
食谱。
def unique_everseen(iterable, key=None):
"List unique elements, preserving order. Remember all elements ever seen."
# unique_everseen('AAAABBBCCDAABBB') --> A B C D
# unique_everseen('ABBCcAD', str.lower) --> A B C D
seen = set()
seen_add = seen.add
if key is None:
for element in ifilterfalse(seen.__contains__, iterable):
seen_add(element)
yield element
else:
for element in iterable:
k = key(element)
if k not in seen:
seen_add(k)
yield element
>>> from itertools import *
>>> lis = ["i","k"]
>>> mydict = OrderedDict([('a', '1'), ('d', '2'), ('f', '1'), ('i', '2'), ('k', '2'), ('m', '1')])
# A list is used in creating the OrderedDict, a dict would lose initial order
>>> OrderedDict((key,mydict[key]) for key in unique_everseen(chain(lis,mydict)))
OrderedDict([('i', '2'), ('k', '2'), ('a', '1'), ('d', '2'), ('f', '1'), ('m', '1')])