使用数组访问多维数组

Question

如果以下是我的问题数组，我如何通过在数组中提供索引值来获得位置[0][2][1]的值，例如:answer = [0, 2, 1]。

   var question = [
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ],
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ],
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ]
    ];
  var answer = [0,2,1];
  question.get(answer); // Is there a way like this?
 之前
有像question.get(answer)或question.get(answer)这样的方法吗?Get ([0,2,1])?

Answer 1

有一个硬编码的方法:

question[answer[0]][answer[1]][answer[2]];

或对于任意长度的数组或嵌套数组:

  var question = [
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ],
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ],
      [
        ['x', 'x', 'x'],
        ['x', 'x', 'x'],
        ['x', 'x', 'x']
      ]
    ];
var answer = [0,2,1];
    var getanswer= function(answerinput,questioninput){
      var val = questioninput;
      answerinput.forEach(function(item){
        val = val[item];
      });
      return val;
    }

    console.log(getanswer(answer,question));

Answer 2

让我们来找点乐子…

Object.prototype.getNestedValue = function(...a) {
  return a.length > 1 ? (this[a[0]] !== void 0 && this[a[0]].getNestedValue(...a.slice(1))) : this[a[0]];
};
var question = [
      [
        ['1', '2', '3'],
        ['4', '5', '6'],
        ['7', '8', '9']
      ],
      [
        ['a', 'b', 'c'],
        ['d', 'e', 'f'],
        ['g', 'h', 'i']
      ],
      [
        [':', ',', '?'],
        ['#', '$', '%'],
        ['+', '!', '&']
      ]
    ];
console.log(question.getNestedValue(...[0,2,1]));
console.log(question.getNestedValue(...[1,2,0]));
console.log(question.getNestedValue(...[2,0,1]));

Answer 3

您可以使用Array#reduce，因为您可以使用question数组作为输入，并通过迭代给定的answer数组获得值作为结果。

var question = [[['000', '001', '002'], ['010', '011', '012'], ['020', '021', '022']], [['100', '101', '102'], ['110', '111', '112'], ['120', '121', '122']], [['200', '201', '202'], ['210', '211', '212'], ['220', '221', '222']]],
    answer = [0, 2, 1],
    getItem = function (array, path) {
        return path.reduce(function (a, p) { return a[p]; }, array);
    };
console.log(getItem(question, answer));

ES6

var question = [[['000', '001', '002'], ['010', '011', '012'], ['020', '021', '022']], [['100', '101', '102'], ['110', '111', '112'], ['120', '121', '122']], [['200', '201', '202'], ['210', '211', '212'], ['220', '221', '222']]],
    answer = [0, 2, 1],
    getItem = (array, path) => path.reduce((a, p) => a[p], array);
console.log(getItem(question, answer));