eregi_replace and Regular Expression Quandry

[saiena]

Is there a way in my regular expression syntax to cause alternating
occurences of the search string to be replaced?

Here's my code:

$item[content] = eregi_replace($search_string, $replace_string,
$item[content]);

This successfully replaces all occurences of $search_string.

Any way to reaplce every other?

[Andy Hassall]

On Mon, 29 Aug 2005 20:55:46 GMT, "saiena" <saiena@nospam_thetellingtree.com>
wrote:

Is there a way in my regular expression syntax to cause alternating
occurences of the search string to be replaced?

Here's my code:

$item[content] = eregi_replace($search_string, $replace_string,
$item[content]);

This successfully replaces all occurences of $search_string.

Any way to reaplce every other?

The solutions I can think of all need non-greedy expressions, at which point
you need to use the PCRE (preg_*) functions - which IMHO is worth switching to
anyway unless you're really tied to the more basic ereg syntax.

At which point you can either use a clever expression, or just do it with
preg_replace_callback and a Boolean flag or counter accessed by the callback to
work out whether it's an odd or even call, and so whether to replace or not.

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[Csaba Gabor]

saiena wrote:

Is there a way in my regular expression syntax to cause alternating
occurences of the search string to be replaced?

$item[content] = eregi_replace($search_string, $replace_string,
$item[content]);

How about using:
$string = preg_replace("/$search_string(.*?($search_string|$))/",
"$replace_string\$1",$string);

where I wrote $string instead of $item[content] cause I didn't
like the looks of that content. This assumes your $search_string
doesn't have unusual characters (in which case you'd need to read up on
regular expressions and escaping characters).

Csaba Gabor from New York