数据编织脚本中的Maps变量查找列表 [英] Lookup list of Maps variable in data weave script

问题描述

我有一个地图列表(listOfMapsObject)，如下所示

I have a list of maps (listOfMapsObject) like below

[
 {
  "Id" : "1234",
  "Value" : "Text1"
  },
  {
  "Id" : "1235",
  "Value" : "Text2"
  }
]

我想在dataweave脚本中访问给定ID的值"字段. 例如:对于Id = 1234，应返回Text1.

I would like access "Value" field for a given Id in dataweave script. For example: For Id = 1234, Text1 should be returned.

%dw 1.0
%output application/json
%var listOfMapsObject = flowVars.listOfMaps
---
payload map {
    "key" : $.key,
    "data" : lookup Value field in listOfMapsObject by given key 
}

推荐答案

@'sulthony h'建议的方法很好，但是如果您在pyload和listOfMapsObject中有大量数据，它将最终导致性能问题.使用filter时，对于有效负载脚本的每个记录，都会为flowVars.listOfMaps中的所有条目循环.

Approch suggested by @'sulthony h' is fine but it will end up in performance issue if you large number of data in pyload and listOfMapsObject. As filter is used , for each record of payload script will loop for all the entries in flowVars.listOfMaps.

以下操作将正常进行，并且仅映射一次键值.

Following will work fine and map key value only once.

%dw 1.0
%output application/json 
%var dataLookup = {(flowVars.listOfMaps map {
        ($.Id): $.Value
     })}
---
payload map {
    key : $.key,
    data : dataLookup[$.key]
}

输出-

[
  {
    "key": "1234",
    "data": "Text1"
  },
  {
    "key": "1235",
    "data": "Text2"
  }
]

有效负载-

[
 {
  "key" : "1234" 
  },
  {
  "key" : "1235"
  }
]

然后-

[
 {
  "Id" : "1234",
  "Value" : "Text1"
  },
  {
  "Id" : "1235",
  "Value" : "Text2"
  }
]

希望这会有所帮助.

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