Question

我有js数组，我使用它作为地图它是动态的（在这个例子中它不是）所以我不知道它会有多少元素我想删除所有发现的元素这是循环后数组的最终视图

movmet_sequence_history:[]
movmet_sequence_history["0"] = "A"
movmet_sequence_history["1"] = "B"
movmet_sequence_history["2"] = "C"
movmet_sequence_history["3"] = "D"
....
....
....
....
movmet_sequence_history["20"] = "Z"

if(movmet_sequence_history["2"] == "C")
{
  //HERE I WANT TO REMOVE THE ELEMENTS "2" ,"1" ,"0"
  //Only the movmet_sequence_history["3"] = "D" will remain
}

更新我不手动删除正确的元素正如我所说，阵列是动态的，我不知道有多少元素将由找到的

组成

Answer 1

你可以将它们定义为未定义。

movmet_sequence_history:[]
movmet_sequence_history["0"] = "A"
movmet_sequence_history["1"] = "B"
movmet_sequence_history["2"] = "C"
movmet_sequence_history["3"] = "D"

if(movmet_sequence_history["2"] == "C")
{
   movmet_sequence_history["0"] = undefined;
   movmet_sequence_history["1"] = undefined;
   movmet_sequence_history["2"] = undefined;
   //Only the movmet_sequence_history["3"] = "D" will remain
}

Answer 2

使用delete运算符。

delete运算符会从对象中删除属性。

＆＃13;

var movement_sequence_history = ["A", "B", "C", "D" ];

if (movement_sequence_history["2"] == "C") {
    delete movement_sequence_history[0];
    delete movement_sequence_history[1];
    delete movement_sequence_history[2];
}

console.log(movement_sequence_history);

＆＃13;

Answer 3

您可以使用array.splice + array.fill。您可以为array.splice提供索引，它将删除该索引之后的所有项并返回它们。

现在你只需清除原始数组中的所有值，并将从splice返回的数组合并到它。

示例

var movmet_sequence_history = []
movmet_sequence_history["0"] = "A"
movmet_sequence_history["1"] = "B"
movmet_sequence_history["2"] = "C"
movmet_sequence_history["3"] = "D"

function removeChar(str) {
  var index = movmet_sequence_history.indexOf(str)
  var _t = movmet_sequence_history.splice(index+1);
  movmet_sequence_history.fill(undefined)
  movmet_sequence_history = movmet_sequence_history.concat(_t)

  console.log(movmet_sequence_history)
}

<button onclick="removeChar('A')">Remove A</button>
<button onclick="removeChar('B')">Remove B</button>
<button onclick="removeChar('C')">Remove C</button>
<button onclick="removeChar('D')">Remove D</button>

JS当我使用数组作为map时，如何从数组中删除元素

3 个答案:

示例