preg_replace help

[penny336]

hi all,
could anyone tell me what's wrong of the following code

$string = '%%this is line 1 level 1??this is line 1 level 2%%this is line 2 level 1%%this is line 3 level 1??this is line 3 level 2%%this is line 4 level 1??this is line 4 level 2&&this is line 4 level3';
/// what an indent looks like
$indent = " --";
/// replace any %% with one indent worth
$result = preg_replace( '/%%/', "\n{$indent}",$string );
/// replace any ?? with two indents worth
$result = preg_replace( '/??/', "\n{$indent}{$indent}",$result );<----- this is has problems (line 9)
/// replace any && with three indents worth
$result = preg_replace( '/&&/', "\n{$indent}{$indent}{$indent}",$result );
/// remove any extra newlines placed at the beginning of the result
$result = preg_replace( '/^\n+/', '', $result );
echo "<pre>";
echo "\nORIGINAL:\n";
echo $string;
echo "\n\nRESULT:\n";
echo $result;
echo "</pre>";

always get the following error at line 9
Warning: Compilation failed: nothing to repeat at offset 0 in c:\apache group\apache\htdocs\jobdbserver\parse.php on line 9

[Mordecai]

You already posted this exact thing... Only post once, or the board gets full of duplicates.

You can delete it by pressing "edit" on your post and clicking "Delete?" and then pressing "Delete Now."

[pHaT-aNt_]

hee, beginners mistake here.

I've recently been reading and learning about regular expressions (aren't they fun? :-P) and im starting to get the hang of them...

the problem with line 9 is the ? character, its a special reserved character in regular expressions.

therefore all special characters wanted as normal matches must be escaped.

I found the following document very handy on understanding the different methods with regular expressions: http://www.devguru.com/.../regexp_special_characters.html
Fixed Code:

$string = '%%this is line 1 level 1??this is line 1 level 2%%this is line 2 level 1%%this is line 3 level 1??this is line 3 level 2%%this is line 4 level 1??this is line 4 level 2&&this is line 4 level3'; 
/// what an indent looks like 
$indent = " --"; 
/// replace any %% with one indent worth 
$result = preg_replace( '/%%/', "\n{$indent}",$string ); 
/// replace any ?? with two indents worth 
$result = preg_replace( '/\\?\\?/', "\n{$indent}{$indent}",$result ); 
/// replace any && with three indents worth 
$result = preg_replace( '/&&/', "\n{$indent}{$indent}{$indent}",$result ); 
/// remove any extra newlines placed at the beginning of the result 
$result = preg_replace( '/^\n+/', '', $result ); 
echo "<pre>"; 
echo "\nORIGINAL:\n"; 
echo $string; 
echo "\n\nRESULT:\n"; 
echo $result; 
echo "</pre>"; 

Gives:

ORIGINAL:
%%this is line 1 level 1??this is line 1 level 2%%this is line 2 level 1%%this is line 3 level 1??this is line 3 level 2%%this is line 4 level 1??this is line 4 level 2&&this is line 4 level3

RESULT:
 --this is line 1 level 1
 -- --this is line 1 level 2
 --this is line 2 level 1
 --this is line 3 level 1
 -- --this is line 3 level 2
 --this is line 4 level 1
 -- --this is line 4 level 2
 -- -- --this is line 4 level3

enjoy my friend.

[penny336]

Dears,

i am just a newbie...........of regular expression...

thx ur help i also suspect it is "keyword" related problem.

but i can't figure out..

so i use str_replace instead of preg_replace.

anyway,

really appreciate ur help

alex