preg ungreedy /U modifier confusion

bubblenut

Hi I've got this little preg

    preg_match_all('/<frame.+src="([^(http:\/\/)].+)".*>/U',$file,$matches);

Which works ok for most instances, it gives

Array
(
    [0] => Array
        (
            [0] => <frame src="left_frame.php" name="leftframe" scrolling="YES" />
            [1] => <frame src="./service/ord_find_intra.php" name="mainframe" />
        )

[1] => Array
    (
        [0] => left_frame.php
        [1] => ./service/ord_find_intra.php
    )

)

However it doesn't match
<frame src="top_frame.htm" name="topframe" scrolling="NO" />
In order to match this I have to use

preg_match_all('/<frame.+src="([^(http:\/\/)]?.+)".*>/U',$file,$matches);

(added the ungreedy ? character after the character class) but surely this shouldn't make a difference if the ungreedy /U modifier is set.
Any ideas?
Thanks
Bubble

swr

As I understand it,

[^(http://)]

Will match any single character except brackets, slashes, colons, and the letters h, t, and p. The contents of [ ] is a character class, and you're trying to put a substring in there. I don't think that is allowed, although I've never attempted it.

I'm not certain about the U flag either. It's simple enough to specify what parts you want ungreedy (.*?) so U seems like a useless flag to me.

rheroux

(added the ungreedy ? character after the character class) but surely this shouldn't make a difference if the ungreedy /U modifier is set.
Any ideas?

Adding the ? character when the U modifier is set makes the pattern greedy rather than ungreedy.

To make ungreedy matches when using the U modifier, use . instead of .?.

bubblenut

Usefull info, thanks. However I still can't work out why it should make a difference in this case, surely this wouldn't make a difference unless there are more [url]http://[/url]'s in a row, which there aren't.
Bubble

xblue

in your first pattern, you define this part

[^([url]http://[/url])]

as required, while it is optional in the second.

i think it won't do what you think it does either way, this might require a lookahead instead, like
code[/code]

HTH