javascript - 如何在javascript/jquery中拼接数组中的值？

Question

我已将数组声明为 var user_profile = []; 并且我已经在 arrayList 中推送了一些数据，其中包含:

[  
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"appeal",
      "assessAmount":"445",
      "assessPenalty":"",
      "assessTotal":445
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"appeal",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"445",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"2075-09-13",
      "assessAmount":"2075-09-03",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"2075-09-13",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":0,
      "assessReason":"2075-09-03",
      "assessTotal":null
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":1,
      "assessReason":"A",
      "assessAmount":"1",
      "assessPenalty":"2",
      "assessTotal":3
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":2,
      "assessReason":"B",
      "assessAmount":"3",
      "assessPenalty":"40",
      "assessTotal":43
   },
   {  
      "assessmentType":"PRE",
      "assessCatId":3,
      "assessReason":"C",
      "assessAmount":"5",
      "assessPenalty":"6",
      "assessTotal":11
   }
]

在这些数组列表中，我需要删除 assessCatId==0 的数据。所以我尝试使用

进行拼接

$.each(user_profile, function(i) {
  if (user_profile[i].assessCatId == 0) {
    user_profile.splice(i, 1);
  }
});

但它不起作用。它向我显示错误:

或者我的意思是说我只需要 arrayList 中 assessCatId==1 或 2 或 3 的数据。 如何过滤此 arrayList 并从 arrayList 中删除这些数据？

Answer 1

在迭代数组时，不要尝试改变(例如拼接)数组 - 这会导致非常不直观的行为。例如，在第一个元素被删除后，进一步迭代的 i 将引用正在迭代的元素使用所在的索引，而不是该元素所在的索引at 在新的变异数组中 - 导致接近尾部时出现未定义问题，并且删除了不正确的索引。

一个简单的 .filter 在这里将是一个更好的选择，不需要 jQuery:

const input=[{"assessmentType":"PRE","assessCatId":0,"assessReason":"appeal","assessAmount":"445","assessPenalty":"","assessTotal":445},{"assessmentType":"PRE","assessCatId":0,"assessReason":"appeal","assessTotal":null},{"assessmentType":"PRE","assessCatId":0,"assessReason":"445","assessTotal":null},{"assessmentType":"PRE","assessCatId":0,"assessReason":"","assessTotal":null},{"assessmentType":"PRE","assessCatId":0,"assessReason":"2075-09-13","assessAmount":"2075-09-03","assessTotal":null},{"assessmentType":"PRE","assessCatId":0,"assessReason":"2075-09-13","assessTotal":null},{"assessmentType":"PRE","assessCatId":0,"assessReason":"2075-09-03","assessTotal":null},{"assessmentType":"PRE","assessCatId":1,"assessReason":"A","assessAmount":"1","assessPenalty":"2","assessTotal":3},{"assessmentType":"PRE","assessCatId":2,"assessReason":"B","assessAmount":"3","assessPenalty":"40","assessTotal":43},{"assessmentType":"PRE","assessCatId":3,"assessReason":"C","assessAmount":"5","assessPenalty":"6","assessTotal":11}]

const output = input.filter(({ assessCatId }) => assessCatId != 0);
console.log(output);