Regular Expressions

[Anon]

Hi, i wrote this code:

<?
$string = '<link>theussername</link><link>theussername</link>';

echo ereg_replace("<link>(.*)</link>", "<a href=\"presentation.php?username=\1\">\1</a>", "$string");
?>

It should convert $string, into two correct links, but instead the output of this is:
<a href="presentation.php?username=theussername</link><link>theussername">theussername</link><link>theussername</a>

Can you help get it right?

[Anon]

The last post was wrong. Here's the correct one.

Hi, i wrote this code:

<?
$string = '&lt;link&gt;theusername&lt;/link&gt;&lt;link&gt;theusername&lt;/link&gt;';

echo ereg_replace("&lt;link&gt;(.*)&lt;/link&gt;", "<a href=\"presentation.php?username=\1\">\1</a>", "$string");
?>

It should convert $string, into two correct links, but instead the output of this is:
<a href="presentation.php?username=theussernametheussername">theussernametheussername</a>

Can you help get it right?

[Anon]

Grr, the site stripped some of my code, here is the correct one 🙁

Hi, i wrote this code:

<?
$string = '&lt;link&gt;theusername&lt;/link&gt;&lt;link&gt;theusername&lt;/link&gt;';

echo ereg_replace("&lt;link&gt;(.*)&lt;/link&gt;", "<a href=\"presentation.php?username=\1\">\1</a>", "$string");
?>

It should convert $string, into two correct links, but instead the output of this is:
<a href="presentation.php?username=holmizen&lt/link&gt;&ltlink&gt;holmizen"&gt;holmizen&lt/link&gt;&ltlink&gt;holmizen</a>

Can you help get it right?

[Anon]

A simple case of greedy quantifiers. If you don't specify otherwise, each * or + or {} you use in a regular expression will try to match the longest possible substring - in this case, everything between the first <link> and the last </link>.

To specify otherwise, put a ? immediately after the , ie., "<link>(.?)</link>"

[Anon]

Huh, I see what you mean. Can someone fix this forum software, please?

Needless to say, the link tags are not being displayed (they're there in the HTML source). They're the things I'm referring to when I say "the first and the last".

"To specify otherwise, put a ? immediately after the *" is a pretty good summary, though.

[Anon]

When I added the ? like (.*?) in my code, it said: "Warning: REG_BADRPT", did i do wrong or is it not working?

[Anon]

Ooh. Didn't expect that :-o

Never saw it before, but then I usually use the preg_* functions - maybe the ereg ones are different that way and I never realised. preg_replace instead of ereg_replace, and "//" around the regexp instead of just "".

preg_replace("/&lt;link&gt;(.*?)&lt;/link&gt;/","&lt;a href=

echo preg_replace("/&lt;link&gt;(.*?)&lt;/link&gt;/", "&lt;a href="presentation.php?username=\1"&gt;\1&lt;/a&gt;", $string);