Python 从字典中返回最大值
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Return the maximum value from a dictionary
提问by Ophilia
I want to return the maximum value and its key from a dictionary, and I know that something like the following should do the trick
我想从字典中返回最大值和它的键，我知道像下面这样的东西应该可以解决问题
max(list.iteritems(), key=operator.itemgetter(1))
However in case that the maximum value in a dictionary is 6 and it happens that multiple keys have the same value .. it will always return the first one ! how can I make it return all the keys that has the maximum number as values along with the value. Here is an example of a dictionary with the same maximum value:
但是，如果字典中的最大值是 6 并且碰巧多个键具有相同的值..它将始终返回第一个！我怎样才能让它返回所有具有最大数量的键作为值以及值。以下是具有相同最大值的字典示例：
dic={0: 1.4984074067880424, 1: 1.0984074067880423, 2: 1.8984074067880425, 3: 2.2984074067880425, 4: 2.2984074067880425}
回答by RomanPerekhrest
The solution using list comprehension:
使用列表理解的解决方案：
dic={0: 1.4984074067880424, 1: 1.0984074067880423, 2: 1.8984074067880425, 3: 2.2984074067880425, 4: 2.2984074067880425}
max_value = max(dic.values()) # maximum value
max_keys = [k for k, v in dic.items() if v == max_value] # getting all keys containing the `maximum`
print(max_value, max_keys)
The output:
输出：
2.2984074067880425 [3, 4]
回答by Willem Van Onsem
You can first determine the maximum with:
您可以首先确定最大值：
maximum = max(dic.values())
and then filterbased on the maximum value:
然后filter基于最大值：
result = filter(lambda x:x[1] == maximum,dic.items())
Example in the command line:
命令行中的示例：
$ python2
Python 2.7.12 (default, Nov 19 2016, 06:48:10)
[GCC 5.4.0 20160609] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> dic={0: 1.4984074067880424, 1: 1.0984074067880423, 2: 1.8984074067880425, 3: 2.2984074067880425, 4: 2.2984074067880425}
>>> maximum=max(dic.values())
>>> maximum
2.2984074067880425
>>> result = filter(lambda x:x[1] == maximum,dic.items())
>>> result
[(3, 2.2984074067880425), (4, 2.2984074067880425)]
Given you want to present the list of keysare a nice list and the value, you can define a function:
鉴于您想显示键列表是一个不错的列表和值，您可以定义一个函数：
def maximum_keys(dic):
maximum = max(dic.values())
keys = filter(lambda x:dic[x] == maximum,dic.keys())
return keys,maximum
which returns a tuple containing the list of keys and the maximum value:
它返回一个包含键列表和最大值的元组：
>>> maximum_keys(dic)
([3, 4], 2.2984074067880425)
