javascript - 如何使用 for in 循环从 Javascript 关联数组中访问特定值以及单个键

Question

这是单个键具有多个值的关联数组

var course ={170:["Introduction to Programming"," Develop algorithms forcomputers",5],
250:[" Web Development","Build web applications",3]};

我想显示其值之一==3的键 即 250:["Web Development","Build web applications",3]};

使用 for in 循环。 谢谢

Answer 1

通用方法

    
    var course ={170:["Introduction to Programming"," Develop algorithms forcomputers",5],
250:[" Web Development","Build web applications",3]};
    
    function printKey(value, arr) {
        for(var i in arr) {
            if(arr.hasOwnProperty(i) && arr[i].indexOf(value) > -1) {
                console.log(arr[i])
            }
        }
    }
    
    printKey(3, course);