regex 4, me 0

[lucianoes]

Here I am again. Still trying to understand regular expressions, particularly those involving line breaks.

This time (still intending to pre-process a text file rather than print anything in a Web page), I have:

bababa
cacaca

dadada
fafafa

That is, a pattern of a pair of lines followed by a blank line. I want to remove all line breaks and separate all elements with a '#' symbol, like this:

bababa#cacaca#dadada#fafafa#...

so I apply:
$result1 = preg_replace ("/\r\n/", "#", $line);

It works. I get:

bababa#cacaca##dadada#fafafa##

Then I made an experiment:
$result1 = preg_replace ("/\r\n/", "#", $line);
$result2 = preg_replace ("/##/", "@", $result1);

I expected to get:

bababa#cacaca@dadada#fafafa@

but instead I get the same:

bababa#cacaca##dadada#fafafa##

if I try:

$result1 = preg_replace ("/\r\n/", "#", $line);
$result2 = preg_replace ("/#/", "@", $result1);

then I get:

bababa@cacaca@@dadada@fafafa@@

Question: how come a single '#' is detected and replaced but '##' is not?

Thanks,
Luciano ES
Santos, SP - Brasil

[znouza]

for me, this is OK

<?
$text="dadasd\nasdas\n\nasdsad\ned23er3";

    echo preg_replace(array("/\n/","/#{1,}"),array("#","#"),$text);

?>