字母解码Javascript

Question

我正在尝试编写一个函数来验证逗号中的所有条目都是数字和显示的。如果他们不是。例如:用户输入2,3,5b，c7我得到的输出是BCE？而不是公元前？这是我试图在其中验证的解码函数：

function fnDecode() {
    var msg = $("textin").value;
        if(msg === "") {
        $("textin_span").innerHTML = "* Please enter a value to decode 
              *";
        $("textin").focus();
    return;
    } else {
        $("textin_span").innerHTML = "";
    }
    var nums = msg.split(","); //split method separates by delimiter
    var outstr = ""; //out string

    for (var i=0; i<nums.length; i++) {
        var n2 = parseInt(nums[i]);
        if (isNaN(n2)) { //if isNaN true, print ?

        outstr += "?";
        } else if (isNallN(nums[i])) { //THIS IS WHERE THE FN GOES
            outstr += "?";

        } else if (n2 === 0) {
            outstr += " ";
        } else if (n2 < 1 || n2 >26) {
            outstr += "?";
        }else {
            outstr += String.fromCharCode(n2+64);
        }
    }
    $("textout").value = outstr;

}

function isNallN(s) {
}

Answer 1

我修正了你的fnDecode函数。

您不需要多个if来检查isNaN，!isNaN('5')将和!isNaN(5)一样工作。有关更多信息，请查看此Javascript等式表。

在这里，我对函数进行了调整，使其能够使用参数中给出的String并返回想要的String。

​

function fnDecode(msg) {
  var nums = msg.split(",");
  var outstr = "";

  for (num of nums) {
    if (isNaN(num)) outstr += "?"; //isNaN works on "5" and 5
    else if (+num === 0) outstr += " "; //We use +num to parse the String to an int
    else if (+num < 1 || +num > 26) outstr += "?";
    else outstr += String.fromCharCode(+num + 64);
  }
  return outstr;

}

var test = '1,2,3,4,5f,6r';
console.log(fnDecode(test));

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

​

下面是一个较短的ES6版本：

​

function fnDecode(msg) {
  return msg.split(',').map( num => isNaN(num) || (+num < 1 || +num > 26) ? '?' : +num == 0 ? ' ' : String.fromCharCode(+num + 64)).join('');
}

var test = '1,2,3,4,5f,6r';
console.log(fnDecode(test));

​