Question

我正在努力检查arry是否包含值。

HTML：

    var newprodata = [];
    var alreadyUsedIds = [];
    angular.forEach(prodata, function(line) {       
        if(line.name === proName || line.brand === proBrand){
            //if (line.id === 183)  {
            var id = parseInt(line.id);
            console.log("line.id",id);
            console.log("alreadyUsedIds",alreadyUsedIds);
            console.log( "alreadyUsedIds.indexOf("+id+")", alreadyUsedIds.indexOf(id) );
            //}
            if (alreadyUsedIds.indexOf(id) > -1){
                console.log("on record pas");
            } else {
                //console.log("line.id",line.id);
                console.log("on record");
                alreadyUsedIds.push(parseInt(id));
                newprodata.push(line);
            }
        }
    });

这是我的控制台output：

alreadyUsedIds [24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36]
0: 24
1: 25
2: 26
3: 27
4: 28
5: 29
6: 30
7: 31
8: 32
9: 33
10: 34
11: 35
12: 36
13: 183
length: 14__proto__: Array[0]      filters.js:46 
alreadyUsedIds.indexOf(183) -1

，它不应该是＆＃39; -1＆＃39;因为＆＃39; 183＆＃39;在阵列中!!!

此外，如果我设置断点，并手动检查我得到：alreadyUsedIds.indexOf（183）= 13

Answer 1

您使用alreadyUsedIds = [24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36] 但是，此数组不包含元素183，因此您不会在那里找到它

有关其工作原理的示例：

＆＃13;

var alreadyUsedIds = [24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36];

// returns -1, because there is no element 183
console.log( alreadyUsedIds.indexOf(183) )

// add 183 to the end of the array
alreadyUsedIds.push(183) 

// returns 13, because the element 183 is at position 13
console.log( alreadyUsedIds.indexOf(183) )

＆＃13;

Answer 2

如果alreadyUsedIds实际上包含183，它可以正常工作，在jsfiddle演示：

https://jsfiddle.net/5qknqgex/

var alreadyUsedIds = [24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 183];
console.log(alreadyUsedIds.indexOf(183));

唯一的解释是你的数组在console.log

时不包含183

Answer 3

它在这里工作

https://jsfiddle.net/jtc2wppu/2/

var alreadyUsedIds = [24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 183];
console.log(alreadyUsedIds.indexOf(183));

javascript .indexOf（）的问题

3 个答案: