Question

找到下面的代码以获取更多详细信息

var A1  = ["1","2","5","6"];

var A2 = [
    {label:"one", value:"1"},
    {label:"two", value:"2"},
    {label:"three", value:"3"},
    {label:"four", value:"4"},
    {label:"five", value:"5"},
    {label:"six", value:"6"},
];
for(var i=0; i<A2.length; i++){
    for(var j=0; j<A1.length; j++ ){
        if(A1[i] == A2[j].value){
            A2[ i ].disabled == true;
        }
        else{
            A2[ i ].disabled == false;
        }
    }
}         
console.log( JSON.stringify( A2 ) );

我想要以下输出：

[{"label":"one","value":"1","disabled":true}, 
{"label":"two","value":"2","disabled":true}, 
{"label":"three","value":"3","disabled":false}, 
{"label":"four","value":"4","disabled":false}, 
{"label":"five","value":"5","disabled":true}, 
{"label":"six","value":"6","disabled":true}]

Answer 1

您需要一个循环，然后检查该值是否在a2中。然后将disabled设置为此布尔值。

在问题中，您将i和j混合在一起，并为a1的任何值设置了一个值。结果或多或少是随机的。

顺便说一句，我将所有变量都更改为小写开头，因为在Javascript中，通常将以大写开头的变量保留给不可理解的函数或类。

var a1 = ["1", "2", "5", "6"],
    a2 = [{ label: "one", value: "1" }, { label: "two", value: "2" }, { label: "three", value: "3" }, { label: "four", value: "4" }, { label: "five", value: "5" }, { label: "six", value: "6" }],
    i;

for (i = 0; i < a2.length; i++) {
    a2[i].disabled = a1.includes(a2[i].value);
}
console.log(a2);

带有注释的代码。

var A1 = ["1", "2", "5", "6"];

var A2 = [
    { label: "one", value: "1" },
    { label: "two", value: "2" },
    { label: "three", value: "3" },
    { label: "four", value: "4" },
    { label: "five", value: "5" },
    { label: "six", value: "6" },
];
for (var i = 0; i < A2.length; i++) {
    A2[i].disabled = false;               // do not use a comparison, take an assignment
                                          // set to false as default value
    for (var j = 0; j < A1.length; j++) {
        if (A1[j] == A2[i].value) {       // i and j switched
            A2[i].disabled = true;        // same here with comparison where you need
                                          // an assignment
        }
    }
}

console.log(JSON.stringify(A2));

Answer 2

我认为您在数组中省略了数字“ 3”，即

var A1 = ["1","2","5","6"];

Answer 3

正在确定范围的原因...

var A1 = ["1", "2", "5", "6"];
var A2 = [{
  label: "one",
  value: "1"
}, {
  label: "two",
  value: "2"
}, {
  label: "three",
  value: "3"
}, {
  label: "four",
  value: "4"
}, {
  label: "five",
  value: "5"
}, {
  label: "six",
  value: "6"
} ];

for (var i = 0; i < A2.length; i++) {
  for (var j = 0; j < A1.length; j++) {
    if (A1[i] == A2[j].value) {
      A2[i].disabled = true;
      console.log(JSON.stringify(A2[i]))
    } else {
      A2[i].disabled = false;
      console.log(JSON.stringify(A2[i]))
    }
  }
}

Answer 4

Array.prototype.map()

map()方法创建一个新数组，其结果是在调用数组中的每个元素上调用提供的函数。

Array.prototype.includes()

includes()方法确定数组是否包含某个元素，并在适当时返回true或false。

使用map()和includes()似乎很直接：

var A1 = ["1","2","5","6"]; 
var A2 = [ {label:"one", value:"1"}, {label:"two", value:"2"}, {label:"three", value:"3"}, {label:"four", value:"4"}, {label:"five", value:"5"}, {label:"six", value:"6"}]; 

A2 = A2.map(i => {
  if(A1.includes(i.value))
    i.disabled = true;
  else
    i.disabled = false;
  return i;
});

console.log( JSON.stringify(A2) );

Answer 5

由于处于嵌套循环状态，因此处于最后状态

for(var i=0; i<A2.length; i++){
    for(var j=0; j<A1.length; j++ ){
        if(A1[i] == A2[j].value){
            A2[ i ].disabled == true;
        }
        else{
            A2[ i ].disabled == false;
        }
    }
}

A2 [i]在每次循环迭代中都会被覆盖，因为它上面的循环会递增j而不是i，因此最后，您只会看到j的最后一个值的影响

已经指出的第二件事是您必须分配

A2[ i ].disabled == true;

使用单个=符号

无法使用下面的对象循环内的以下代码循环数组获取正确的输出，即仅在最后条件下循环

5 个答案: