Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

The regex is as follows 

$saved_trade_search =~ m/\<td align=\"left\" valign=\"bottom\"\>(*)\<c
+enter\>\<form action=\'gpost.phtml\' method=\'post\'>/;

my $saved_lot = $1;
print $saved_lot;

[download]
And it's resulting in the error "Quantifier follows nothing in regex; marked by <-- HERE in m/<td align="left" valign="bottom">(* <-- HERE )<center><form action='gpost.phtml' method='post'>/ at test.pl line 68.".

Any ideas what I did wrong or what this error means?

Replies are listed 'Best First'.
Re: Having a regex error
by injunjoel (Priest) on Oct 04, 2005 at 16:39 UTC
    Greetings,
    You forgot the dot so (.*?) instead of (*) . The '*' tells how many of the proceeding characters to grab (in this case zero or more) and '.' means anything including space.

    -InjunJoel
    "I do not feel obliged to believe that the same God who endowed us with sense, reason and intellect has intended us to forego their use." -Galileo
[reply]
[d/l]
[select]
Re: Having a regex error
by ikegami (Patriarch) on Oct 04, 2005 at 16:41 UTC

    "*" means "0 or more of the atom preceeds it". But there's nothing between the "*" and the previous special character ((). Did you mean ".*", perhaps. "." means "any character", so ".*" means "0 or more characters".

    By the way, everyone one of your "\" are useless.

[reply]
[d/l]
[select]
Re: Having a regex error
by blazar (Canon) on Oct 04, 2005 at 16:43 UTC
    I suspect you're confusing regexen with shell patterns. Hence * should become .* or 
    s/\*/.*/;  # ;-)

    [download]

    But said this, weren't you told not to try and parse HTML yourself?

[reply]
[d/l]
[select]
      I did get it fixed, I forgot the .* (yes I feel stupid and it's been a while). I was told NOT to use regexes to parse HTML a number of times but I generally pull through it okay. No idea what the issue is this time around but it won't pull back any data between the two sections of code listed above. I even applied /gix and it still comes back empty.

      I know some of the / were useless but I had to try to see if I could figure out what's wrong.. Anything in the code that might be the problem for not matching anything?

[reply]
        "I even applied /gix and it still comes back empty."

        That doesn't surprise me. Do you know what /g, /i and /x do? The /x is certainly going to stop your regex from working, since it ignores whitespace, which is a crucial part of your regex.

        I'm guessing the problem is that the text includes newlines in between the two tags you're matching between, and the . metacharacter does NOT match newlines UNLESS you add the /s modifier to the regex.

        Just tacking modifiers on all willy-nilly does not make a regex work.

        Jeff japhy Pinyan, P.L., P.M., P.O.D, X.S.: Perl, regex, and perl hacker
        How can we ever be the sold short or the cheated, we who for every service have long ago been overpaid? ~~ Meister Eckhart
[reply]
[d/l]
        Greetings again,
        One other thing to try is the use of the

        's' => "single-line"
        vs.
        'm' => "multi-line"

        switches at the end of your match, which basically deal with newlines differently. In short 's' treats newlines differently (so they get treated as if they are a part of '.') and 'm' does not. So you might want to try 
        m/\Q<td align="left" valign="bottom">\E(.*?)\Q<center><form action='gp
+ost.phtml' method='post'>\E/s #Notice the 's' at the end here.

        [download]
        Read more... (347 Bytes)


        -InjunJoel
        "I do not feel obliged to believe that the same God who endowed us with sense, reason and intellect has intended us to forego their use." -Galileo
[reply]
[d/l]
[select]
        I was told NOT to use regexes to parse HTML a number of times but I generally pull through it okay.
        Don't mind. Every now and again I do it myself... although I guess I should be supposed not to say so here!! So pssst...
        I know some of the / were useless but I had to try to see if I could figure out what's wrong.. Anything in the code that might be the problem for not matching anything?
        Hmmm... do you mean \ (a.k.a. backslashes)? Anyway, no: at first sight I don't see anything wrong. But I'm tired, and I suppose that an HTML-extracting module would do better than me!
[reply]
[d/l]

Back to Seekers of Perl Wisdom