javascript 从字符串中删除最后一行
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Remove last line from string
提问by user1534664
How do I remove the last line "\n" from a string, if I dont know how big the string will be?
如果我不知道字符串有多大，如何从字符串中删除最后一行“\n”？
var tempHTML = content.document.body.innerHTML;
var HTMLWithoutLastLine = RemoveLastLine(tempHTML);
function RemoveLastLine(tempHTML)
{
// code
}
回答by rekire
Try:
尝试：
if(x.lastIndexOf("\n")>0) {
return x.substring(0, x.lastIndexOf("\n"));
} else {
return x;
}
回答by Julien Royer
You can use a regular expression (to be tuned depending on what you mean by "last line"):
您可以使用正则表达式（根据“最后一行”的含义进行调整）：
return x.replace(/\r?\n?[^\r\n]*$/, "");
回答by Marco Roy
A regex will do it. Here's the simplest one:
正则表达式会做到这一点。这是最简单的一种：
string.replace(/\n.*$/, '')
\nmatches the last line break in the string
\n匹配字符串中的最后一个换行符
.*matches any character, between zero and unlimited times (except for line terminators). So this works whether or not there is content on the last line
.*匹配零次和无限次之间的任何字符（行终止符除外）。所以无论最后一行是否有内容，这都有效
$to match the end of the string
$匹配字符串的结尾
回答by Ivo
In your specific case the function could indeed look like:
在您的特定情况下，该功能确实看起来像：
function(s){
return i = s.lastIndexOf("\n")
, s.substring(0, i)
}
Though probably you dont want to have spaces at the end either; in this case a simple replace might work well:
尽管您可能也不希望末尾有空格；在这种情况下，简单的替换可能效果很好：
s.replace(/s+$/, '')
Keep in mind however that new versions of Javascript (ES6+) offer shorthand ways of doing this with built-in prototype functions (trim, trimLeft, trimRight)
但是请记住，新版本的 Javascript ( ES6+) 提供了使用内置原型函数（trim、trimLeft、trimRight）执行此操作的速记方法
s.trimRight()
Cheers!
干杯!
