在preg_replace（）函数中循环遍历ol标记

Question

I am trying to replace new lines of a code with html ol tag to display the code as

1. Line 1
2. Line 2
3. Line 3
4. Line 4

Here is my php

$x="Line 1
      Line 2
      Line 3
      Line 4";

 echo preg_replace("/
+([^
]+)/","<ol start='1'><li>$1</li></ol>",$x);

The problem is ol tag is not looping in the preg_replace() function,so It outputs

1. Line 1
1. Line 2
1. Line 3
1. Line 4

What is wrong with the code?

Answer 1

You are creating multiply ol tags instead of wrapping the ol around the preg_replace function. You can also simplify your regex with the m modifier:

$x="Line 1 
      Line 2 
      Line 3 
      Line 4";

echo "<ol start='1'>" . preg_replace("/^(.*?)$/m", "<li>$1</li>", $x) . "</ol>";

Alternative if you don't want the trailing newlines simply use:

/^(.*?)\s?$/m

When this modifier is set, the "start of line" and "end of line" constructs match immediately following or immediately before any newline in the subject string, respectively, as well as at the very start and end. This is equivalent to Perl's /m modifier.

Source: php.net