在php中用文本替换小于**（＆lt;）**和大于**（＆gt;）**的符号

Question

我搜索了一段时间的脚本，可以看到html标签和＆lt;之间的区别。和＆gt;放在文字中， 原因是我从数据库接收文本， 哪个是由html表单插入的，包含text和html标签， 文本可以包含＆lt;和＆gt;，标签也一样， 使用htmlspecialchars，您可以将文本验证为XHTML， 但您也会将标记更改为<b>到<b>， 所以我需要一个可以看出这两者之间差异的脚本......

请解决我的问题。

Answer 1

如果我们可以假设......

• html标记中的＆lt; 和＆gt; 字符未包含，带有空格
• 相同的字符在条件中被空格包围
• 在条件下，这些组合存在＆lt; ，＆gt; ，＆lt; = ，＆gt; = ， ！＆lt; ，！＆gt;

......这可能是一个解决方案：

$result = preg_replace('/ ([!]{0,1})(<)([=]{0,1}) /', '$1&lt;$3', $string);
$result = preg_replace('/ ([!]{0,1})(>)([=]{0,1}) /', '$1&lt;$3', $result);

这是正则表达式对＆lt; 字符的含义：

\         # Match the character “ ” literally
(         # Match the regular expression below and capture its match into backreference number 1
   [!]       # Match the character “!”
      {0,1}      # Between zero and one times, as many times as possible, giving back as needed (greedy)
)
(         # Match the regular expression below and capture its match into backreference number 2
   <         # Match the character “<” literally
)
(         # Match the regular expression below and capture its match into backreference number 3
   [=]       # Match the character “=”
      {0,1}      # Between zero and one times, as many times as possible, giving back as needed (greedy)
)
\         # Match the character “ ” literally