如果留空，则从 GCD 计算中删除第三个输入

Question

我正在使用以下代码计算用户提供的三个数字的 GCD：

$('#calc').click(function(){

Math.GCD = function(numbers) {
  for (var i = 1 ; i < numbers.length ; i++){
    numbers[0] = twogcd(numbers[0], numbers[i]);
  }
  return numbers[0];

  function twogcd(first, second) {
    if (first < 0) first = -first;
    if (second < 0) second = -second;
    if (second > first) {var temp = first; first = second; second = temp;}
    while (true) {
        first %= second;
        if (first == 0) return second;
        second %= first;
        if (second == 0) return first;
    }
   }
};

Math.LCM = function(first,second) {
    return first * (second / this.GCD(first, second));
};

var first   = document.getElementById("first").value;
var second   = document.getElementById("second").value;
var third = document.getElementById("third").value;

var numbers = [first,second,third];

var GCDresult = Math.GCD(numbers);


alert(GCDresult);
});

与 HTML:

<FORM NAME="calc" method="POST">

<button TYPE="button" ID="calc">CALC</button>
<input type="text" name="stuff[]" class="input-field" id="first"/>
<input type="text" name="stuff[]" class="input-field" id="second"/>
<input type="text" name="stuff[]" class="input-field" id="third"/>

</FORM>

但是，我希望此表单根据用户输入的内容计算 2 和 3 数字的 GCD。因此，如果一个字段留空，null 字段将被忽略，GCD 计算将继续处理两个输入。但是，作为 JavaScript 的新手，我无法弄清楚如何排除空字段。

Fiddle: https://jsfiddle.net/tjj7won4/40/

我该如何修改代码来解决这个问题？

Answer 1

在将值发送到 GCD 函数之前过滤掉 non-numeric 个值，例如

/* Filter out things that don't look like numbers */
var numbers = [first,second,third].filter(function (e, i, a) { /* e = element, i = index, a = array */
    return parseFloat(e); /* Is it numeric? */
});

演示

$('#calc').click(function(){

Math.GCD = function(numbers) {
  for (var i = 1 ; i < numbers.length ; i++){
    numbers[0] = twogcd(numbers[0], numbers[i]);
  }
  return numbers[0];

  function twogcd(first, second) {
    if (first < 0) first = -first;
    if (second < 0) second = -second;
    if (second > first) {var temp = first; first = second; second = temp;}
    while (true) {
        first %= second;
        if (first == 0) return second;
        second %= first;
        if (second == 0) return first;
    }
   }
};

Math.LCM = function(first,second) {
    return first * (second / this.GCD(first, second));
};

var first   = document.getElementById("first").value;
var second   = document.getElementById("second").value;
var third = document.getElementById("third").value;

/* Filter out things that don't look like numbers */
var numbers = [first,second,third].filter(function (e, i, a) { /* e = element, i = index, a = array */
 return parseFloat(e); /* Is it numeric? */
});

var GCDresult = Math.GCD(numbers);


alert(GCDresult);
});

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

<FORM NAME="calc" method="POST">

<button TYPE="button" ID="calc">CALC</button>
<input type="text" name="stuff[]" class="input-field" id="first"/>
<input type="text" name="stuff[]" class="input-field" id="second"/>
<input type="text" name="stuff[]" class="input-field" id="third"/>

</FORM>

Answer 2

更新了您的代码。添加了对第一个输入字段 isEmpty 的检查。如果是，则为其分配下一个非空输入字段的值。

更新了 JS：

$('#calc').click(function(){

Math.GCD = function(numbers) {
  for (var i = 1 ; i < numbers.length ; i++){
    if(numbers[0]==""){
            $.each($('.inputField'),function(){
          if($(this).val()!=""){
               numbers[0] = $(this).val();
               return false;
          }
        });
    }   
    if(numbers[0]!="" && numbers[i]!=""){
        numbers[0] = twogcd(numbers[0], numbers[i])
    }
  }
  return numbers[0];

 if (numbers[i] === '' || numbers[i] === 0) { 
    numbers[0] = twogcd(numbers[0], numbers[i])
    };
  function twogcd(first, second) {
    if (first < 0) first = -first;
    if (second < 0) second = -second;
    if (second > first) {var temp = first; first = second; second = temp;}
    while (true) {
        first %= second;
        if (first == 0) return second;
        second %= first;
        if (second == 0) return first;
    }
   }
};

Math.LCM = function(first,second) {
    return first * (second / this.GCD(first, second));
};

var first   = $("#first").val();
var second   = $("#second").val();
var third = $("#third").val();

var numbers = [first,second,third];

var GCDresult = Math.GCD(numbers);


alert(GCDresult);
});

update fiddle link

如果留空，则从 GCD 计算中删除第三个输入

Remove third input from GCD calculation if left blank

javascript

jquery

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