Javascript 如何删除最后一个逗号？

How to Remove last Comma?

提问by Sanju

This code generates a comma separated string to provide a list of ids to the query string of another page, but there is an extra comma at the end of the string. How can I remove or avoid that extra comma?

此代码生成一个逗号分隔的字符串，以向另一个页面的查询字符串提供 id 列表，但字符串末尾有一个额外的逗号。我怎样才能删除或避免那个额外的逗号？

<script type="text/javascript">
    $(document).ready(function() {
        $('td.title_listing :checkbox').change(function() {
            $('#cbSelectAll').attr('checked', false);
        });
    });
    function CotactSelected() {
        var n = $("td.title_listing input:checked");
        alert(n.length);
        var s = "";
        n.each(function() {
            s += $(this).val() + ",";
        });
        window.location = "/D_ContactSeller.aspx?property=" + s;
        alert(s);
    }
</script>

回答by Sam Doshi

Use Array.join

用 Array.join

var s = "";
n.each(function() {
    s += $(this).val() + ",";
});

becomes:

变成：

var a = [];
n.each(function() {
    a.push($(this).val());
});
var s = a.join(', ');

回答by Amarghosh

s = s.substring(0, s.length - 1);

回答by CMS

You can use the String.prototype.slicemethod with a negative endSliceargument:

您可以使用String.prototype.slice带有否定endSlice参数的方法：

n = n.slice(0, -1); // last char removed, "abc".slice(0, -1) == "ab"

Or you can use the $.mapmethod to build your comma separated string:

或者您可以使用该$.map方法来构建逗号分隔的字符串：

var s = n.map(function(){
  return $(this).val();
}).get().join();

alert(s);

回答by Guffa

Instead of removing it, you can simply skip adding it in the first place:

您可以简单地跳过首先添加它，而不是删除它：

var s = '';
n.each(function() {
   s += (s.length > 0 ? ',' : '') + $(this).val();
});

回答by Sender

Using substring

使用 substring

var strNumber = "3623,3635,";

document.write(strNumber.substring(0, strNumber.length - 1));

Using slice

使用 slice

document.write("3623,3635,".slice(0, -1));

Using map

使用 map

var strNumber = "3623,3635,";

var arrData = strNumber.split(',');

document.write($.map(arrData, function(value, i) {
  return value != "" ? value : null;
}).join(','));

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

Use Array.join

用 Array.join

var strNumber = "3623,3635,";
var arrTemp = strNumber.split(',');
var arrData = [];

$.each(arrTemp, function(key, value) {
  //document.writeln(value);
  if (value != "")
    arrData.push(value);
});

document.write(arrData.join(', '));

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

回答by miku

Using 'normal' javascript:

使用“普通”javascript：

var truncated = s.substring(0, s.length - 1);

回答by o.k.w

A more primitive way is to change the eachloop into a forloop

更原始的方法是将each循环改为for循环

for(var x = 0; x < n.length; x++ ) {
  if(x < n.length - 1)
    s += $(n[x]).val() + ",";
  else
    s += $(n[x]).val();
}

回答by Joel Mueller

Sam's answer is the best so far, but I think mapwould be a better choice than eachin this case. You're transforming a list of elements into a list of their values, and that's exactly the sort of thing mapis designed for.

到目前为止，山姆的答案是最好的，但我认为在这种情况下，地图将是比每个都更好的选择。您正在将元素列表转换为它们的值列表，而这正是map设计的目的。

var list = $("td.title_listing input:checked")
    .map(function() { return $(this).val(); })
    .get().join(', ');

Edit: Whoops, I missed that CMS beat me to the use of map, he just hid it under a slicesuggestion that I skipped over.

编辑：哎呀，我错过了 CMS 击败我使用map，他只是在slice我跳过的建议下隐藏了它。

回答by Vikas Kottari

you can use below extension method:

您可以使用以下扩展方法：

String.prototype.trimEnd = function (c) {
    c = c ? c : ' ';
    var i = this.length - 1;
    for (; i >= 0 && this.charAt(i) == c; i--);
    return this.substring(0, i + 1);
}

So that you can use it like :

这样你就可以像这样使用它：

var str="hello,";
str.trimEnd(',');

Output: hello.

输出：你好。

for more extension methods, check below link: Javascript helper methods

有关更多扩展方法，请查看以下链接： Javascript 辅助方法

回答by Kaya M

Here is a simple method:

这是一个简单的方法：

    var str = '1,2,3,4,5,6,';
    strclean = str+'#';
    strclean = $.trim(strclean.replace(/,#/g, ''));
    strclean = $.trim(str.replace(/#/g, ''));