將多行換成段落

Question

我想從一個字符串中找到段落，並將其格式化，我有什么樣的作品，但它不能100％工作。

所以，我有這個看起來像這樣的字符串：

##Chapter 1

Once upon a time there was a little girl named sally, she went to school.

One day it was awesome!

##Chapter 2

We all had a parade!

我正在通過將##...轉換為<H2>來格式化字符串，現在看起來像這樣：

<h2>Chapter 1</h2>

Once upon a time there was a little girl named sally, she went to school.

One day it was awesome!

<h2>Chapter 2</h2>

We all had a parade!

現在，我想將所有內容都轉換為一個段落，然后執行以下操作：

// Converts sections to paragraphs:
$this->string = preg_replace("/(^|\n\n)(.+?)(\n\n|$)/", "<p>$2</p>", $this->string);

// To Remove paragraph tags from header tags (h1,h2,h3,h4,h5,h6,h7):
$this->string = preg_replace("/<p><h(\d)>(.+?)<\/h\d><\/p>/i", "<h$1>$2</h$1>", $this->string);

這是最終輸出（為便於閱讀，添加了新行）：

<h2>Chapter 1</h2>
Once upon a time there was a little girl named sally, she went to school.
<p>One day it was awesome!</p>
<h2>Chapter 2</h2>
<p>We all had a parade!</p>

正如我在開始時所說的那樣，這並不能100％起作用，並且您可以看到沒有在第一段中添加一段。 我該怎么做才能改善正則表達式？

Answer 1

您可以一步完成：

$this->string = preg_replace('~(*BSR_ANYCRLF)\R\R\K(?>[^<\r\n]++|<(?!h[1-6]\b)|\R(?!\R))+(?=\R\R|$)~u',
                             '<p>$0</p>', $this->string);

圖案細節

(*BSR_ANYCRLF)       # \R can be any type of newline
\R\R                 # two newlines
\K                   # reset the match
(?>                  # open an atomic group
    [^<\r\n]++       # all characters except <, CR, LF
  |                  # OR
    <(?!h[1-6]\b)    # < not followed by a header tag
  |                  # OR
    \R(?!\R)         # single newline
)+                   # close the atomic group and repeat one or more times
(?=\R\R|$)           # followed by to newlines or the end of the string

Answer 2

將m開關添加到第一個正則表達式。

// Converts sections to paragraphs:
$this->string = preg_replace("/(^|\n\n)(.+?)(\n\n|$)/m", "<p>$2</p>", $this->string);

// To Remove paragraph tags from header tags (h1,h2,h3,h4,h5,h6,h7):
$this->string = preg_replace("/<p><h(\d)>(.+?)<\/h\d><\/p>/i", "<h$1>$2</h$1>", $this->string);