在字典python中访问列表中的项目 [英] Accessing items in lists within dictionary python

问题描述

我有一本字典，该字典具有与列表关联的键.

I have a dictionary that has keys associated with lists.

mydict = {'fruits': ['banana', 'apple', 'orange'],
         'vegetables': ['pepper', 'carrot'], 
         'cheese': ['swiss', 'cheddar', 'brie']}

我想做的是使用一个if语句，如果我在字典中的任何列表中搜索item及其项，它将返回键.这就是我正在尝试的:

What I want to do is use an if statement that if I search for item and its in any of the lists within the dictionary it will return the key. This is what I was trying:

item = cheddar
if item in mydict.values():
    print key 

但是它什么也没做，输出应该是:

but it doesn't do anything, the output should be:

cheese

这似乎很简单，但是我无法弄清楚.任何帮助都很棒.

This seems like a simple thing but I just can't figure it out. Any help is awesome.

推荐答案

您必须使用for，简单的if不足以检查一组未知的列表:

You'll have to use a for, a simple if is not enough to check an unknown set of lists:

for key in mydict.keys():
    if item in mydict[key]:
        print key

没有显式for语句的方法可能是这样的:

An approach without an explicit for statement would be possible like this:

foundItems = (key for key, vals in mydict.items() if item in vals)

返回与item关联的所有键.但是在内部，仍然存在某种迭代.

which returns all keys which are associated with item. But internally, there's still some kind of iteration going on.

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