从字符串中删除最后一个逗号 [英] Remove Last Comma from a string

问题描述

使用JavaScript，如何删除最后一个逗号，但前提是逗号是最后一个字符，或者逗号后面只有空格?这是我的代码. 我有一个正在工作的小提琴.但是它有一个错误.

Using JavaScript, how can I remove the last comma, but only if the comma is the last character or if there is only white space after the comma? This is my code. I got a working fiddle. But it has a bug.

var str = 'This, is a test.'; 
alert( removeLastComma(str) ); // should remain unchanged

var str = 'This, is a test,'; 
alert( removeLastComma(str) ); // should remove the last comma

var str = 'This is a test,          '; 
alert( removeLastComma(str) ); // should remove the last comma

function removeLastComma(strng){        
    var n=strng.lastIndexOf(",");
    var a=strng.substring(0,n) 
    return a;
}

推荐答案

这将删除最后一个逗号及其后的所有空格:

This will remove the last comma and any whitespace after it:

str = str.replace(/,\s*$/, "");

它使用正则表达式:

• /标记正则表达式的开始和结束

• The / mark the beginning and end of the regular expression

,与逗号匹配

\s表示空白字符(空格，制表符等)，而*表示0个或更多

The \s means whitespace characters (space, tab, etc) and the * means 0 or more

末尾的$表示字符串的末尾

The $ at the end signifies the end of the string

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