正则表达式表达删除开始到结束字符字符串

Question

我有这个字符串：

var string = "From: Jeremy<br /> 
Sent: 22 Apr 2016 12:08:03</br /> 
To: Mark<br /> 
Subject: Another test email<br /><br /> 

Hi Mark, 
<br /> 
I'm sending this email as a way to test the email! 
<br /> 
Cheers, 
<br /> 
Jeremy" 

而且我想，所以我得到的电子邮件正文拼接从一开始这个字符串直到“主题”行之后内容。

我已经试过这至今：

string.substring(string.lastIndexOf('Subject'), string.length - 1) 

但这个选项不会从字符串返回主题行也是如此。

有没有我可以使用的正则表达式库？

Answer 1

使用string.replace你可以这样做：

var body = string.replace(/^[\s\S]*\s+Subject: [^\n]*\n+/, '') 

代码：

var string = `From: Jeremy<br /> 
 
Sent: 22 Apr 2016 12:08:03</br /> 
 
To: Mark<br /> 
 
Subject: Another test email<br /><br /> 
 

 
Hi Mark, 
 
<br /> 
 
I'm sending this email as a way to test the email! 
 
<br /> 
 
Cheers, 
 
<br /> 
 
Jeremy` 
 

 
var body = string.replace(/^[\s\S]*\s+Subject: [^\n]*\n+/, '') 
 

 
document.writeln("<pre>" + body + "</pre>")

[\s\S]*匹配0或多个任意字符，包括换行符。之后是Subject:也被删除。

输出：

"Hi Mark, 
<br /> 
I'm sending this email as a way to test the email! 
<br /> 
Cheers, 
<br /> 
Jeremy" 

Answer 2

有人会给你非正则表达式的解决方案，但这里是一个用正则表达式

[\s\S]*Subject\s*:.*([\s\S]+) <-- your result in first capturing group 

Regex Demo

JS演示

var re = /[\s\S]*Subject\s*:.*([\s\S]+)/gm; 
 
var str = `From: Jeremy<br /> 
 
Sent: 22 Apr 2016 12:08:03</br /> 
 
To: Mark<br /> 
 
Subject: Another test email<br /><br /> 
 

 
Hi Mark, 
 
<br /> 
 
I'm sending this email as a way to test the email! 
 
<br /> 
 
Cheers, 
 
<br /> 
 
Jeremy` 
 
var m = re.exec(str); 
 
document.writeln("<pre>" + m[1] + "</pre>");