找出变量是否在数组中？ [英] Find out if a variable is in an array?

问题描述

我有一个变量：

var code = "de";

我有一个数组：

var countryList = ["de","fr","it","es"];

有人可以帮助我，因为我需要检查变量是否在countryList数组中 - 我的尝试在这里：

Could someone help me as I need to check to see if the variable is inside the countryList array - my attempt is here:

    if (code instanceof countryList) {
        alert('value is Array!');
    } 

    else {
        alert('Not an array');
    }

但是在运行时我在console.log中收到以下错误：

but I get the following error in console.log when it's run:

TypeError：无效'instanceof'操作数countryList

TypeError: invalid 'instanceof' operand countryList

推荐答案

jQuery有一个实用程序函数来查找元素是否存在于数组中

jQuery has a utility function to find whether an element exist in array or not

$.inArray(value, array)

它返回中的值的索引数组和 -1 如果数组中不存在值。所以你的代码可以是这样的

It returns index of the value in array and -1 if value is not present in array. so your code can be like this

if( $.inArray(code, countryList) != -1){
     alert('value is Array!');
} else {
    alert('Not an array');
}

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