Question

我想按3个属性进行分组，但不是每个属性都是它自己的嵌套数组。我想要的是什么：

 def values=[
     [day:1,month:1,year:1],
     [day:1,month:1,year:1],
     [day:2,month:1,year:1],
     [day:2,month:2,year:1]
 ];

 /*...some code to group by DAY, MONTH, AND YEAR

 ..desired result is that items with the same day, 
  month, and year end up in a one level deep subarray
 */

  [
    [[day:1,month:1,year:1],[day:1,month:1,year:1]],  
    [[day:2,month:1,year:1]] ,
    [[day:2,month:2,year:1]] 
  ];

使用带有多个闭包的 groupBy（）方法，我将每个分组属性作为自己的嵌套数组，如[year [month [day []]]]，这是不是什么我需要。

Answer 1

您希望采用groupBy函数来执行您需要的操作。在此示例中，您的地图已经存在您要将其分组的身份。所以这足以满足您的需求：

Swift_TransportException in StreamBuffer.php line 269: Connection could not be established with host mailtrap.io [Connection refused #111]

如果您确实在地图中有更多值，则可以使用def values=[ [day:1,month:1,year:1], [day:1,month:1,year:1], [day:2,month:1,year:1], [day:2,month:2,year:1], ] // just the identity println values.groupBy().values() // => [[[day:1, month:1, year:1], [day:1, month:1, year:1]], [[day:2, month:1, year:1]], [[day:2, month:2, year:1]]]分组到一个级别：

subMap

在挑剔的一面：那些是你得到的嵌套地图。

Answer 2

考虑以下使用inject来构建一个映射，其键是适当的组，值是所需的列表：

（修改：更新地图密钥的构造，每条评论）

def values=[
     [day:1,month:1,year:1],
     [day:1,month:1,year:1],
     [day:2,month:1,year:1],
     [day:2,month:2,year:1]
 ];

def groupMap = [:].withDefault{ key -> [] }

def result = values.inject(groupMap) { val, m -> 
    val["${m.'day'}:${m.'month'}:${m.'year'}"] << m 
    val
}.values()

assert [[day:1, month:1, year:1], [day:1, month:1, year:1]] == result[0]
assert [[day:2, month:1, year:1]] == result[1]
assert [[day:2, month:2, year:1]] == result[2]

由多个属性分组的Groovy方法只有一个级别

2 个答案: