[英]Getting the maximum key value pair in a Scala map by value
I am trying to pull the maximum value form a map along with its key. 我试图从地图及其键中拉出最大值。 For example:
例如:
val map = Map('a' -> 100, 'b' -> 23, ... 'z' -> 56)
Where 100 is the largest value, how would I go about pulling ('a',100)? 如果100是最大值,我将如何拉('a',100)? I essentially want to use Map.max but search by value rather than key.
我基本上想要使用Map.max但是按值而不是键搜索。
You can use maxBy
with a function from the key-value pair to just the value: 您可以将
maxBy
与键值对中的函数一起使用,只使用值:
val map = Map('a' -> 100, 'b' -> 23, 'z' -> 56)
map.maxBy(_._2) // (a,100)
This is a short form for 这是一个简短的表格
map.maxBy { case (key, value) => value }
A slight modification in case the max value you are looking for is present more than once in the map: 如果您要查找的最大值在地图中出现多次,则稍作修改:
// Find the entries with the max value in the map
val maxValue = map.maxBy(item => item._2)
// Filter the map and retain the entries with the max value
map.filter(item => item._2 == maxValue._2)
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