Question

我有一个对象，需要在其中找到特定的项目索引号。以下是我的对象：

[
  {
    "type": "Grayscale",
    "mode": "average"
  }, {
    "type": "Sepia"
  }, {
    "type": "Invert",
    "invert": true
  }, {
    "type": "Convolute",
    "opaque": false,
    "matrix": [1, 1, 1, 1, 0.7, -1, -1, -1, -1]
  }, {
    "type": "Convolute",
    "opaque": false,
    "matrix": [0, -1, 0, -1, 5, -1, 0, -1, 0]
  }, {
    "type": "Brownie"
  }, {
    "type": "Brightness",
    "brightness": 0.35
  }
]

例如，我需要找到Invert属性具有值type的项目的索引号。因此，在这种情况下，输出应为2。我只需要搜索type键的值。

Answer 1

通过传递提供的 callback 函数作为参数，可以使用findIndex方法。

let arr = [ {"type":"Grayscale","mode":"average"}, {"type":"Sepia"}, {"type":"Invert","invert":true}, {"type":"Convolute","opaque":false,"matrix":[1,1,1,1,0.7,-1,-1,-1,-1]}, {"type":"Convolute","opaque":false,"matrix":[0,-1,0,-1,5,-1,0,-1,0]}, {"type":"Brownie"}, {"type":"Brightness","brightness":0.35} ], key = 'type';
console.log(arr.findIndex(elem => elem[key] == 'Invert'));

Answer 2

以下是该代码的简短摘要。

var sample = [{"type":"Grayscale","mode":"average"},{"type":"Sepia"},{"type":"Invert","invert":true},{"type":"Convolute","opaque":false,"matrix":[1,1,1,1,0.7,-1,-1,-1,-1]},{"type":"Convolute","opaque":false,"matrix":[0,-1,0,-1,5,-1,0,-1,0]},{"type":"Brownie"},{"type":"Brightness","brightness":0.35}]  

function findIndex(data, keyfield, value){
  
  return data.indexOf(data.find(function(el,index){
    return el[keyfield] === value;
  }));
}

console.log(findIndex(sample, 'type', 'Invert'));

Answer 3

您可以使用下划线或loadash（_）包。它具有对阵列操作的多种功能支持。

const _ = require('lodash')

let your_array=  [
      {"type":"Grayscale","mode":"average"},
      {"type":"Sepia"},
      {"type":"Invert","invert":true},
      {"type":"Convolute","opaque":false,"matrix":[1,1,1,1,0.7,-1,-1,-1,-1]},
      {"type":"Convolute","opaque":false,"matrix":[0,-1,0,-1,5,-1,0,-1,0]},
      {"type":"Brownie"},
      {"type":"Brightness","brightness":0.35}
    ];
    let objectIndex = _.findIndex(your_array, each_element=> each_element.type == "Invert");
    alert(objectIndex)

在数组中查找具有特定键值的对象的索引

3 个答案: