正則表達式刪除字符串中字符的開始到結尾

Question

我有這個字符串：

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"

並且我想從頭開始拼接該字符串，直到“主題”行之后，以便獲得電子郵件正文內容。

到目前為止，我已經嘗試過了：

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

但是此選項的確從字符串中返回主題行。

我可以使用正則表達式庫嗎？

Answer 1

使用string.replace可以執行以下操作：

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

碼：

 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個或多個任何字符，包括換行符。 緊隨其后的是Subject:行。

輸出：

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

Answer 2

有人會給您非正則表達式的解決方案，但這是一個帶有正則表達式的解決方案

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

正則表達式演示

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>");