使用值返回数组(Javascript)

时间:2014-03-03 14:34:49

标签: javascript arrays

如果您只知道其中一个值,是否可以获取数组?

我有两个数组,想找到哪一个有变量:

var fruit = ["apple","banana","orange"];
var veggie = ["carrot","pea","corn"];
alert("An apple is a " + /*return array with value "apple"*/);

是否可以使用Javascript执行此操作?感谢

5 个答案:

答案 0 :(得分:1)

在if / else语句中包含警报并检查'apple'的索引。如果fruit.indexOf('apple') != -1那么它必须是一个水果。

答案 1 :(得分:0)

您可以使用如下所示的函数,并在每个相关的数组上调用它:

function contains(a, obj) {   //a is the array to check, and obj the object you are looking for
    var i = a.length;
    while (i--) {
       if (a[i] === obj) {
           return true;
       }
    }
    return false;
}

答案 2 :(得分:0)

我会使用一个对象来包含各种类型:

var type = {
  fruit: ["apple", "banana", "orange"],
  veggie: ["carrot", "pea", "corn"]
}

如果你想找到数组的名称,那么东西就是在对象中的数组上循环,使用indexOf来测试该东西的存在。

function findThing(thing) {
  for (var k in type) {
    if (type[k].indexOf(thing) > -1) return k;
  }
  return 'unknown';
}

console.log('An apple is a ' + findThing('apple')); // An apple is a fruit
console.log('An froom is a ' + findThing('froom')); // An froom is a unknown

Fiddle

另一方面,如果您想要返回更多信息(例如类型,大小和其他项目,您可以这样做:

function returnArrayOfThing(thing) {
  for (var k in type) {
    if (type[k].indexOf(thing) > -1) return k + ' which contains ' + type[k].length + ' items: ' + type[k];
  }
  return 'unknown';
}

console.log('An apple is in ' + returnArrayOfThing('apple')); // An apple is in fruit which contains 3 items: apple,banana,orange

答案 3 :(得分:0)

如果你只有两个类别,那么你可以做一个简单的检查:

var fruit = ["apple","banana","orange"];
var veggie = ["carrot","pea","corn"];

var typeOfApple = 'unknown';

if (fruit.indexOf('apple') !== -1) {
  typeOfApple = 'fruit';
} else if (veggie.indexOf('apple') !== -1) {
  typeOfApple = 'veggie';
}
alert("An apple is a " + typeOfApple);

如果您有更多类别(或者只是希望您的代码更加健壮),您可以使用带有键的对象作为类别,并使用该类别中的项目来表示数组:

var types = {
  fruit : ["apple","banana","orange"],
  veggie : ["carrot","pea","corn"]
}

然后,您可以检查每个类别是否包含您的项目:

var typeOfApple = 'unknown';

for (var type in types) {
  if (types[type].indexOf('apple') !== -1)
    typeOfApple = type;
}


alert("An apple is a " + typeOfApple);

答案 4 :(得分:0)

使用该对象包含这两个数组。

JSFIDDLE

var food = {
    fruit : ["apple","banana","orange"],
    veggie : ["carrot","pea","corn"]
}

var arr = getFood('apple', food);
//returns ["apple","banana","orange"];

 var arr2 = getFood('pea', food);
//returns ["carrot","pea","corn"];

function getFood(item, food){
    for (var key in food){
        if(food[key].indexOf(item) != -1){
            return food[key];
        }
    }
}