eregi is loose!

webchef

Hello again..

i use the following function to place a series of pictures (their names and location) in an array:

function getFiles($dirname, $key) {  

	 $handle=opendir($dirname); 
	 while ($file = readdir($handle)) 
	 { 
			if($file=='.'||$file=='..') 
				continue; 
			else 
			{ 
				if (eregi($key, $file)) {    $result_array[]=$file; } 
			} 
	 } 
	 closedir($handle); 
	 return $result_array; 
 } 
 $a = $auto_id . "_";
 $pictures = getFiles("images", $a);

the above function works great except for one problem. If $auto_id is lets say 5, i only want files that look like this: 5_1.jpg, 5_2.gif, 5_x.x

my problem is that it also retrieves files with a number or character BEFORE the 5, which i don't want. like this: 25_1.jpg, 15_3.gif... so on and so forth..

how do i set it so it doesn't look for a character before the 5...

hope i explained it well.

Mike

leatherback

Hi,

Hm.. Couldn't you use the position of the first match? If the position is not at the start of the string, you ignore that value?

webchef

yeah i suppose i could..

but im not sure how to do that..

I mean how do i set eregi to only return according to the first match?

i'm still learning all these new functions like ereg.. so im not fully aware of all thier uses..

perhaps you can show me an example?

Thanks

Mike

Bootsman123

Only retrieve the the files with $auto_id in it:

<?php
$string = "6_jdfkjd";
$auto_id = 5;
$a = $auto_id . "_";
if (preg_match("/$a(.*?)/si", $string)) {
echo "Auto_id: $auto_id is in it.";
} else {
echo "Auto_id: $auto_id is not in it.";
}
?>

webchef

I can't use that boot...

it doesn't match the function... i need something that works with the function, which already works so well...

there must be a way to do this

Weedpacket

Um, I'm kinda stepping in a bit late here, but...

You want to find strings of the form Nn.a, where n is digits, a is letters, and N is $auto_id. But you don't want to match MNn.a just because the sequence of digits MN happens to end in N; so if $auto_id is 5, you want to match 5_12.jpg, 5_88.gif, but not 25_91.jpg.

It's going to be a real pain doing this with ereg, because the regexp syntax it uses is not sophisticated enough. The PCRE syntax of preg_match() on the other hand is sophisticated enough to make it fairly simple. (preg_match() is also faster than ereg()...)

So, digits ($auto_id, in fact), followed by _ followed by digits, followed by . followed by letters.

if(preg_match("/(?<!\d){$auto_id}_\d+\.[a-z]+/i", $string, $matches))
{  ... the first match is in $matches[0]...
}

Dissecting that regexp:

/
Start of the regexp.
color=darkblue[/color]
Something called a "negative lookbehind assertion". Fancy way of saying that "the matched string must not be preceded by anything matching this", where in this case "this" is \d - PCRE for a digit. The upshot of this is that if you're looking for "5", "25" won't match because the "5" is preceded by a digit.
{$auto_id}
$auto_id itself - wrapped in {} to stop PHP getting confused about where the variable name ends.
_
An underscore.
\d+
More digits
.
A .
[a-z]+
One or more letters
/
End of the regexp
i
Case-insensitive matching. I could have left this off and used [a-zA-Z] instead, I suppose...

Note also that there is preg_match_all(), which will return all matches of the pattern with one call.

webchef

i have to be honest..

i only skimmmed your post to see what you are talking about and perhaphs learning something new.. but i have already solved it.. it was actually quite easy.. look at the entire function...

then look at the line:

$a = $auto_id . "_";

to make it work i changed it to:

$a = '^' . $auto_id . "_";

and it works like a charm..

the entire script for what i was trying to do is at the following post...

http://www.phpbuilder.com/board/showthread.php?threadid=10238216

check it out.. and thanks for the help. late or not.. its much appreciated..

Mike

CaptianChaos

From the original post:

if (eregi($key, $file)) { $result_array[]=$file; }

Change it to:

if (eregi("^$key_", $file)) { $result_array[]=$file; }

And you're done.

The new way means this:
^ = starts with
say $key = 5, then it must start with a 5, followed by an underscore.

oops, sorry, I am repeating what you already said. I see you have it solved, oh well, I'm posting anyway.