Question

我用数组方法解决了一个练习;我应该输入一个数字，返回的值应该是相同的数字，每两个连续的偶数之间用短划线。

到目前为止，我已经编写了这段代码但是它返回了一个空数组，如果你能指出我的错误而不是提供另一种解决方案会好得多。

function dashit(num){ 
   //test num = 025468, expected arr = ["0","-","2","5","4","-","6","-  ","8"]
    var arr = [];
    var prog = num.toString().split(""); // I suppose ["0","2","5","4","6","8"]
    for (var i = 0; i<num.length; i = i + 2){
        if (num[i] % 2 == 0 ){ // case of "0" and "2"
            if (num[i+1] % 2 == 0){
                arr.push(prog[i]); // "0" pushed from prog to arr
                arr.push("-");     // "-" pushed from prog to arr
                arr.push(prog[i+1]); // "2" pushed from prog to arr
            }
        }
        else { // case of "5" and "4"
                arr.push(prog[i]);  // "5" pushed from prog to arr
                arr.push(prog[i+1]); // "4" pushed from prog to arr
        }
    }
    return arr;
}

Answer 1

您正在比较num var，您必须比较prog var：

    function dashit(num){ 
    var prog = num.toString().split(""); // I suppose ["0","2","5","4","6","8"]
    for (var i = 0; i<prog.length; i = i + 2){
        if (prog[i] % 2 == 0 ){ // case of "0" and "2"
            if (prog[i+1] % 2 == 0){
}

Answer 2

您正在将num作为octal号码（从0开始）

尝试将其作为string

传递

dashit("025468");

参见工作示例：

function dashit(num){ 
  
    var arr = [];
    
    for (var i = 0; i<num.length; i = i + 2){
        if (num[i] % 2 == 0 ){ // case of "0" and "2"
            if (num[i+1] % 2 == 0){
                arr.push(num[i]); // "0" pushed from prog to arr
                arr.push("-");     // "-" pushed from prog to arr
                arr.push(num[i+1]); // "2" pushed from prog to arr
            }
        }
        else { // case of "5" and "4"
                arr.push(num[i]);  // "5" pushed from prog to arr
                arr.push(num[i+1]); // "4" pushed from prog to arr
                arr.push("-");
        }
    }
    return arr;
} 


document.write(JSON.stringify(dashit("025468")));

Answer 3

此问题非常适合使用递归。我确定你的老师想要的是什么; - ）

＆＃13;

var n = '02546878642';

var isPair = function(n1, n2) {
  return Number(n1) % 2 == 0 && Number(n2) % 2 == 0;
};

var result = (function f(i, o) {

  if (i.length < 1) return o;
  var first = i.shift();
  var next =  i[0];
  o.push(first);
  if (isPair(first, next)) {
    o.push('-');
  }
  return f(i, o);
})(n.split(''), []);



$('#result').html(result.join(''));

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id='result'>result</div>

＆＃13;

如何将数字转换为字符串并将其推入JavaScript中的数组？

3 个答案: