如果元素存在，则使用 Dataweave 将键添加到数组

如何解决如果元素存在，则使用 Dataweave 将键添加到数组

我有一个 JSON 对象，其中包含主题 1、主题 2、主题 3 等字段，并以字符串数组作为值。

如果分配给字段 subject1、subject2、subject3 的字符串数组中存在任何搜索元素，那么我需要将 Json 对象中的键或该字段添加到现有数组 (myArray)，

    %dw 2.0
    var myArray = [];
    var subjects = {
    "subject1" = ["sectionA","sectionB","sectionC"],"subject2" = ["sectionB","sectionD","sectionE"],"subject3" = ["sectionC","sectionF","sectionG"],}
    
    fun getSubjects(section) = mapping mapObject ((value,key,index) ->
       if(value contains key) myArray << key
       else myArray 
    )

    ---

    {
      "subjects" : getSubjects(var.section) // var.section = sectionA
    }

但我收到此错误“无法将数组强制转换为对象”。有没有更好的方法来做到这一点？

解决方法

我认为这就是你想要做的；因为数据在 dataweave 中是不可变的，如果您想在更改数组内容之类的内容的同时迭代集合，则必须使用诸如 reduce 之类的东西。

%dw 2.0

var subjects = {
    "subject1": ["sectionA","sectionB","sectionC"],"subject2": ["sectionB","sectionD","sectionE"],"subject3": ["sectionC","sectionF","sectionG"]
}

var section = "sectionA"

fun getSubjects(section) = subjects pluck $$ reduce ((subject,myArray=[]) ->
    if (subjects[subject] contains section) myArray << subject
    else myArray
)

---
{
    subjects: getSubjects(section)
}

产量：

{
  subjects: [
    "subject1"
  ]
}

,

还有一种方法可以做到这一点，如下所示，我们发送变量和需要匹配的字符串

%dw 2.0
var myArray = []
var subjects = {
"subject1" : ["sectionA","subject2" : ["sectionA","subject3" : ["sectionC","sectionG"],}
 
fun adding(inputarray,matchingkey)= flatten(inputarray mapObject ((value,key) -> 
 (("myArray"): (myArray ++ [key])) if ((value) contains matchingkey) 
 ) pluck $)
 
---
 
adding(subjects,"sectionC")

输出为：

[
  "subject1","subject3"
]