Question

我有此命令dict od：

OrderedDict([('and', 1), ('that', 1), ('this', 1), ('of', 1), ('truly', 1), ('something', 1), ('nothing', 1), ('important', 2), ('is', 3)])

我正在尝试以相反的顺序打印此词典的键值对。我尝试过：

for k,v in od.items()[-1:]:
    print k,v

它打印：

is 3

但是它仅输出最后一个键值对，即('is',3)。我希望所有的键值对都按相反的顺序排列：

is 3
important 2
nothing 1
something 1
truly 1
of 1
this 1
that 1
and 1

有办法吗？

Answer 1

使用reversed

例如：

from collections import OrderedDict

d = OrderedDict([('and', 1), ('that', 1), ('this', 1), ('of', 1), ('truly', 1), ('something', 1), ('nothing', 1), ('important', 2), ('is', 3)])

for k, v in reversed(d.items()):   #or for k, v in d.items()[::-1]
    print(k, v)

输出：

is 3
important 2
nothing 1
something 1
truly 1
of 1
this 1
that 1
and 1

Answer 2

reversed是最好的选择，但是如果您想保留切片的话：

for k, v in od.items()[::-1]:
    print k, v

Answer 3

这是因为列表切片中存在错误。

for k,v in od.items()[-1:] 从最后一个元素迭代到最后（仅打印最后一个元素）

Understanding slice notation

如果您只想更改代码

for k,v in od.items()[::-1]: # iterate over reverse list using slicing
    print(k,v)

Answer 4

od = OrderedDict([('and', 1), ('that', 1), ('this', 1), ('of', 1), ('truly', 1), ('something', 1), ('nothing', 1), ('important', 2), ('is', 3)])
od_list=[i for i in od.items()]

#Reverse the list
od_list.reverse()

#Create the reversed ordered List.
od_reversed=OrderedDict(od_list)
print(od_reversed)
    OrderedDict([('is', 3),
             ('important', 2),
             ('nothing', 1),
             ('something', 1),
             ('truly', 1),
             ('of', 1),
             ('this', 1),
             ('that', 1),
             ('and', 1)])

有没有办法以相反的顺序打印字典？

4 个答案: