PHP替换，但替换替换字符串 [英] PHP Replace, But Alternate Replace String

问题描述

好的，这就是我要做的事情:我试图使用PHP开发本质上是markdown实现的 tiny 子集，而不是使用完整的markdown类.

Okay, here's what I'm trying to do: I'm trying to use PHP to develop what's essentially a tiny subset of a markdown implementation, not worth using a full markdown class.

我本质上需要做一个str_replace，但是每次出现针时都要替换替换字符串，以便处理打开和关闭HTML标记.

I need essentially do a str_replace, but alternate the replace string for every occurrence of the needle, so as to handle the opening and closing HTML tags.

例如，斜体是一对星号(如* this *)，而代码块则由反引号(如"this")包围.

For example, italics are a pair of asterisks like *this*, and code blocks are surrounded by backticks like `this`.

我需要用对应的开头HTML标记替换第一次出现的两个字符对，然后用结束标记替换第二个字符.

I need to replace the first occurrence of a pair of the characters with the opening HTML tag corresponding, and the second with the closing tag.

关于如何执行此操作的任何想法?我发现会涉及某种正则表达式...

Any ideas on how to do this? I figured some sort of regular expression would be involved...

推荐答案

我个人将每次出现*或\的过程都用一个计数器循环，然后根据该字符用相应的HTML标记替换计数(例如，如果计数为偶数并且您打了星号，则将其替换为<em>，如果它是奇数，则将其替换为</em>，依此类推.)

Personally, I'd loop through each occurrence of * or \ with a counter, and replace the character with the appropriate HTML tag based on the count (for example, if the count is even and you hit an asterisk, replace it with <em>, if it's odd then replace it with </em>, etc).

但是，如果您确定只需要支持几种简单的标记，则针对每种标记的正则表达式可能是最简单的解决方案.像这样的星号，例如(未经测试):

But if you're sure that you only need to support a couple simple kinds of markup, then a regular expression for each might be the easiest solution. Something like this for asterisks, for example (untested):

preg_replace('/\*([^*]+)\*/', '<em>\\1</em>', $text);

反斜杠也类似.

这篇关于PHP替换，但替换替换字符串的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！