Groovy：如何通过属性将地图列表合并到单个地图，将不同的地图值组合到内部列表中

Question

我想将地图列表（实际上是带有jeft连接多对多关系表的查询的结果列表）合并到一个地图，该地图将包含单个key：value对（如果它们相等）在所有映射和键中：[值列表]，以防某个键的值不同。例如，有一个地图列表：

[  
[name:john, title:senior, access:floor1],  
[name:john, title:senior, access:floor2]  
]

到地图

[name:john, title:senior, access:[floor1, floor2]]

Answer 1

给定地图输入列表：

def input = [  
    [name:'john', title:'senior', access:'floor1'],  
    [name:'john', title:'senior', access:'floor2'],  
    [name:'carol', title:'senior', access:'floor2']
]

我们可以按前两个分组（同样，作为地图）：

input.groupBy { [name: it.name, title: it.title] }

哪个给我们：

[
    [name:john, title:senior]:[
        [name:john, title:senior, access:floor1],
        [name:john, title:senior, access:floor2]
    ],
    [name:carol, title:senior]:[
        [name:carol, title:senior, access:floor2]
    ]
]

然后我们可以按照所需的输出形式将它们收集起来，给我们：

input.groupBy { [name: it.name, title: it.title] }.collect { k, v ->
    k + [access: v.access]
}

哪个给出结果：

[
    [name:john, title:senior, access:[floor1, floor2]],
    [name:carol, title:senior, access:[floor2]]
]