Question

var caseOne = [
    {"name":"Felicity", "gender":"F", ...   ... ,"type":"Admin"},
    {"name":"Tony", "gender":"M", ...   ... ,"type":""},
    .
    .
    .
    .
    {"name":"Super Man", "gender":"M", ...   ... ,"type":""},
    {"name":"Wonder Women", "gender":"F", ...   ... ,"type":""},
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F", ...   ... ,"type":"Admin"},
    {"name":"Tony", "gender":"M", ...   ... ,"type":""},
    .
    .
    .
    .
    {"name":"Super Man", "gender":"M", ...   ... ,"type":""},
    {"name":"Wonder Women", "gender":"F", ...   ... ,"type":""},
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"},
    {"name":"Bat man", "gender":"M", ...   ... ,"type":""}
];

我有这种阵列。我想要在lastIndexOf "type":""之后的所有记录，意味着从cansOne它将返回最后3条记录，并且从caseTwo它将返回0条记录。简而言之，"type":""之后的所有记录。任何人都可以提供帮助。

提前致谢。

预期输出

caseOne = [
    {"name":"Hulk", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Loky", "gender":"M", ...   ... ,"type":"User"},
    {"name":"Thore", "gender":"M", ...   ... ,"type":"Admin"}
];

caseTwo = [];

Answer 1

创建一个可重用的函数getIndex()，它将获取一个数组参数，并使用type: ""为您提供该对象的最后一个索引。使用此索引，您可以splice()结果并获得所需的输出

var caseOne = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M","type":""},
    {"name":"Super Man", "gender":"M","type":""},
    {"name":"Wonder Women", "gender":"F" ,"type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M" ,"type":"User"},
    {"name":"Thore", "gender":"M" ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M" ,"type":""},
    {"name":"Super Man", "gender":"M" ,"type":""},
    {"name":"Wonder Women", "gender":"F","type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M","type":"User"},
    {"name":"Thore", "gender":"M","type":"Admin"},
    {"name":"Bat man", "gender":"M","type":""}
];

function getIndex(caseArray){
  var arrayIndex;
  caseArray.forEach(function(caseOneObj, index){
    if(caseOneObj.type === ''){
      arrayIndex = index;
    }
  });
  return arrayIndex;
}

var index = getIndex(caseOne);
var resultCaseOne = caseOne.splice(index+1, caseOne.length);
console.log('-----caseOne-----');
console.log(resultCaseOne);

index = getIndex(caseTwo);
var resultCaseTwo = caseTwo.splice(index+1, caseTwo.length);
console.log('-----caseTwo-----');
console.log(resultCaseTwo);

但是，如果你有最后一个数组最有可能type:''的对象数组，那么你可以从该数组的最后一个对象开始搜索该索引，如下所示：

var caseOne = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M","type":""},
    {"name":"Super Man", "gender":"M","type":""},
    {"name":"Wonder Women", "gender":"F" ,"type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M" ,"type":"User"},
    {"name":"Thore", "gender":"M" ,"type":"Admin"}
];

var caseTwo = [
    {"name":"Felicity", "gender":"F" ,"type":"Admin"},
    {"name":"Tony", "gender":"M" ,"type":""},
    {"name":"Super Man", "gender":"M" ,"type":""},
    {"name":"Wonder Women", "gender":"F","type":""},
    {"name":"Hulk", "gender":"M","type":"User"},
    {"name":"Loky", "gender":"M","type":"User"},
    {"name":"Thore", "gender":"M","type":"Admin"},
    {"name":"Bat man", "gender":"M","type":""}
];

function getIndex(caseArray){
  var i;
  for(i=caseArray.length-1; i>0; i--){
   if(caseArray[i].type === ''){
      break;
    }
  }
  return i;
}

var index = getIndex(caseOne);
var resultCaseOne = caseOne.splice(index+1, caseOne.length);
console.log('-----caseOne-----');
console.log(resultCaseOne);

index = getIndex(caseTwo);
var resultCaseTwo = caseTwo.splice(index+1, caseTwo.length);
console.log('-----caseTwo-----');
console.log(resultCaseTwo);

Answer 2

通过这种方式获得这些数组元素将会解决什么问题？因为在某个元素之后，搜索数组以找到所有内容后，可能会有更好的方法。无论如何，你;正在寻找像：

这样的代码

＆＃13;

// source data
const source = [
    {"name":"Felicity", "gender":"F", "type":"Admin"},
    {"name":"Tony", "gender":"M", "type":""},
    {"name":"Super Man", "gender":"M", "type":""},
    {"name":"Wonder Women", "gender":"F", "type":""},
    {"name":"Hulk", "gender":"M", "type":"User"},
    {"name":"Loky", "gender":"M", "type":"User"},
    {"name":"Thore", "gender":"M", "type":"Admin"}
];
const lastIndex = Array
	.from( source ) // Clone the array so reversing does not affect the source.
	.reverse() // Reverse the array so we can use findIndex instead of writing findLastIndex ourselves.
	.findIndex( entry => !entry.type ); // Get the index of the first element that has no type.
const result = source.slice( source.length - lastIndex, source.length ); // Slice the orginal array.
console.log( result );

＆＃13;

AngularJS - 从数组中获取最后一个空白元素的索引

3 个答案: