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Accepted
Telion
Asked:2020-10-24 10:56:39 +0000 UTC2020-10-24 10:56:39 +0000 UTC

更改数组的一个元素会覆盖整个数组

  • 772

该类有一个方法：

constructor(id) {
  this.position = [6, 4];
  this.LABYRINTH = init2DArray(8, 8, {lookaround: false, events: false});
  this.lookedaround.bind(this);
}

lookedaround() {
  //this.position задан в конструкторе: this.position = [6, 4];
  this.LABYRINTH[this.position[0]][this.position[1]].lookaround = true;
}

空白数组填充功能：

function init2DArray(xlen, ylen, data) {
  var ret = [];
  for (var x = 0; x < xlen; x++) {
    ret[x] = [];
    for (var y = 0; y < ylen; y++) {
      ret[x][y] = data;
    }
  }
  return ret;
}

当我简单地调用该方法时，lookedaround整个数组被覆盖，将每个值替换为true. 我不明白为什么会这样……

而已：

player.LABYRINTH.forEach((e, o) => {
  e.forEach((i, p) => {
    console.log(`[${o}, ${p}] = ${i.lookaround}`);
  });
});
[0, 0] = false
[0, 1] = false
[0, 2] = false
[0, 3] = false
[0, 4] = false
[0, 5] = false
[0, 6] = false
[0, 7] = false
[1, 0] = false
[1, 1] = false
[1, 2] = false
[1, 3] = false
[1, 4] = false
[1, 5] = false
[1, 6] = false
[1, 7] = false
[2, 0] = false
[2, 1] = false
[2, 2] = false
[2, 3] = false
[2, 4] = false
[2, 5] = false
[2, 6] = false
[2, 7] = false
[3, 0] = false
[3, 1] = false
[3, 2] = false
[3, 3] = false
[3, 4] = false
[3, 5] = false
[3, 6] = false
[3, 7] = false
[4, 0] = false
[4, 1] = false
[4, 2] = false
[4, 3] = false
[4, 4] = false
[4, 5] = false
[4, 6] = false
[4, 7] = false
[5, 0] = false
[5, 1] = false
[5, 2] = false
[5, 3] = false
[5, 4] = false
[5, 5] = false
[5, 6] = false
[5, 7] = false
[6, 0] = false
[6, 1] = false
[6, 2] = false
[6, 3] = false
[6, 4] = false
[6, 5] = false
[6, 6] = false
[6, 7] = false
[7, 0] = false
[7, 1] = false
[7, 2] = false
[7, 3] = false
[7, 4] = false
[7, 5] = false
[7, 6] = false
[7, 7] = false

player.lookedaround();

player.LABYRINTH.forEach((e, o) => {
  e.forEach((i, p) => {
    console.log(`[${o}, ${p}] = ${i.lookaround}`);
  });
});
[0, 0] = true
[0, 1] = true
[0, 2] = true
[0, 3] = true
[0, 4] = true
[0, 5] = true
[0, 6] = true
[0, 7] = true
[1, 0] = true
[1, 1] = true
[1, 2] = true
[1, 3] = true
[1, 4] = true
[1, 5] = true
[1, 6] = true
[1, 7] = true
[2, 0] = true
[2, 1] = true
[2, 2] = true
[2, 3] = true
[2, 4] = true
[2, 5] = true
[2, 6] = true
[2, 7] = true
[3, 0] = true
[3, 1] = true
[3, 2] = true
[3, 3] = true
[3, 4] = true
[3, 5] = true
[3, 6] = true
[3, 7] = true
[4, 0] = true
[4, 1] = true
[4, 2] = true
[4, 3] = true
[4, 4] = true
[4, 5] = true
[4, 6] = true
[4, 7] = true
[5, 0] = true
[5, 1] = true
[5, 2] = true
[5, 3] = true
[5, 4] = true
[5, 5] = true
[5, 6] = true
[5, 7] = true
[6, 0] = true
[6, 1] = true
[6, 2] = true
[6, 3] = true
[6, 4] = true
[6, 5] = true
[6, 6] = true
[6, 7] = true
[7, 0] = true
[7, 1] = true
[7, 2] = true
[7, 3] = true
[7, 4] = true
[7, 5] = true
[7, 6] = true
[7, 7] = true

javascript

1 个回答

  1. Best Answer

    因为数组的所有元素都是对同一个对象的引用。

    function init2DArray(xlen, ylen, dataCreator) {
  var ret = [];
  for (var x = 0; x < xlen; x++) {
    ret[x] = [];
    for (var y = 0; y < ylen; y++) {
      ret[x][y] = dataCreator();
    }
  }
  return ret;
}

this.LABYRINTH = init2DArray(8, 8, function() {
  return { lookaround: false, events: false };
});
    • 1

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