helpy help with readdir creating an array

vaska

having some problems...the problem is that the readdir is not creating an array that works...does anybody know what i'm doing wrong (i'm a little over my head with this)...

thanks...jv

$handle=opendir('.') or die("Cannot Open Dir");
while ($file=readdir($handle)) {
if ($file != "." && $file != "..") {
echo "<a href=\"$file\">$file</a>\n";

/////////// - below is just not working...it's just not getting what i need...?

$files[]=$file;
}
}

$query = mysql_query ("SELECT * FROM temp2 WHERE html NOT IN ($files) " ) or die ("Unexpected error for MySQL database [3b]");
$row = mysql_fetch_array($query);

suntra

I don't think you can send an array to MySQL the way you do it. PHP would simply write "Array" in your MySQL query statement...

vaska

oh...yep...that's what i'm getting...array, array, array...

how should i do this?

xblue

Hi,

I tried to explain that in your other thread, maybe not clear enough, so I'll give it another try:

The mysql query expects a string if you use WHERE column_name IN (...). So you'll need to create the string, e.g. by replacing

$files[]=$file;

with

$files.="'$file', ";

This should concatenate all desired file names, each in single quotes.

Then, outside the while loop, get rid of the last comma and space. Simply

$files=substr($files, 0, -2);

should do, I think, though you may use any other way you like to create a string like this.

vaska

thanks xb...

you are right...i didn't understand that...i've been pretty successful so far learning how to do many things, even solving many of my own problems, but this one is tricky...i've tried a few methods, some of which were successful but weren't really good solutions...so i've been playing with the idea you suggested...

however, i get an error message as it seems that the array will not pass through the query...i'm just not sure what to try with this...

error code = "Unexpected error for MySQL database [3b]"

code =

$handle=opendir('.') or die("Cannot Open Dir");
while ($file=readdir($handle)) {
if ($file != "." && $file != "..") {
$files.="'$file', ";
}
}
closedir($handle);

$query_not = mysql_query ("SELECT * FROM temp2 WHERE html NOT IN ($files) ORDER by html ASC " ) or die ("Unexpected error for MySQL database [3b]");
$row_not = mysql_fetch_array($query_not);

if i take out NOT IN it processes the query, but i obviously don't get the correct results...when i use <? echo $files; ?> (to check to see if it's working) it DOES prove that it is passing the values...so the final sticking point (i guess) is that that the query won't deal with the values that $files is creating...???

Weedpacket

Well the problem is that your $files string gets built with an extra comma hanging off the end.

Many people building such lists up check at every iteration to see if this is the first, or last, item to be added, and use that to decide whether or not to add the comma. Others put the first element in by hand, and then the loop appends comma-element pairs for the rest. I think both solutions look messy, though, and can become confusing. So I do it this way:

Instead of $files .= "'$file', "; have $files[] = "'$file'"; (watch the quotes!). Then after the loop turn the array into a comma-separated string by saying $files = join(',', $files);. And put that into your query.

vaska

i'm beginning to understand these things now...i have to visualize things in my head often before i understand them (being a designer and all)...weedy, you really explain things very well...it's just a hunch that you teach or are in a position where you instruct people during the day...

i tried your alteration however...and i got this...

Fatal error: [] operator not supported for strings in /home/path/main.php on line 19

this line -> $files[] = " '$file' ";

i did check the output though with my previous method...and i am getting results like this from $files...'a.html''b.html''c.html'...single quotes...

i'm running php 4.2.3...???

Weedpacket

Whups; looks like $files has already been given a string value when the loop starts! Actually I should have guessed as much - sorry; if you set PHP's error reporting high enough it would have complained about uninitialised variables when you wrote the original code.

So my guess is that you've got some line of the form $files=''; or such like before the loop, so that it starts out as an empty string? If that's the case, then you'll want to initialise it to an empty array instead; $files=array();.

If that's not the case, then - well, $files is getting some sort of string value from somewhere, and it has to be happening before the loop.

Weedpacket

So this is what I get, starting with the code in your original post:

$files=array();
$handle=opendir('.') or die("Cannot Open Dir");
while($file=readdir($handle)) {
	if($file != "." && $file != "..") {
		echo "<a href=\"$file\">$file</a>\n";
		$files[]="'$file'";
	}
}
$files = join(',', $files);

$query = mysql_query("SELECT * FROM temp2 WHERE html NOT IN($files) ") or
	die("Unexpected error for MySQL database [3b]");
$row = mysql_fetch_array($query);

How does that go?

vaska

it goes very well...but...

it returns results that are in the table and NOT in the dir...

the goal was the opposite of the results i'm getting now...to return values that are IN the dir, but NOT in the table...

i'll try to see if i can reverse the results...

thanks very much though for helping me with this Weedy (and others too)...jv

Weedpacket

Fnord.

Well, one obvious point is that it's difficult to get something out of the table if it's not in there to begin with ...

Here's something you can do:

Get a list of all the unique filenames in the table.

$result = mysql_query('SELECT DISTINCT html FROM temp2');

Read through the result list, and put all of them into an array $files_in_table.

while(list($files_in_table[]) = mysql_fetch_row($result))
{/*empty loop!*/}

(Just too elegant for my own good ... can't help it: it was originally

while($row = mysql_fetch_array($result))
{ $files_in_table=$row['html'];
}

[Edit: Indeed - way too elegant. I usually use a for() statement to loop through recordsets, so I didn't notice a bug that comes of using while(). Use the "expanded" version.)

You don't want any of the files in that list.

Now use that same directory-reading loop you've got now to build up a similar array listing all the files in the directory - $files_in_directory. You'll be wanting some of the files in that list.

So now you've got $files_in_table - an array of all the files listed in your table, and $files_in_directory, an array of the (interesting) files you've got in your directory. You want an array of all the files in the directory, except those that are in the table. PHP gives you a function for that:

$wanted_files = array_difference($files_in_directory, $files_in_table);

Code_guy

very elegant solution Weedpacket
although if he meant the values that are in the dir and in the table all you need is to remove the NOT from:
WHERE html NOT IN($files)

vaska

shuckks...this takes me full circle...i've been here before now...

the problem with array_diff and array_merge/array_unique is that they don't relate the information properly...once they encounter the first instance of a difference they lose control and then begin outputting completely the wrong results (i've posted about this before)...

i think doing it completely with a mysql query makes the most sense, but HOW is the question...

i have a backup method that i can use to do this unfortunately...it's manual process...so i'm covered...

thanks for all the help on this one...jv

Weedpacket

Originally posted by Code_guy
very elegant solution Weedpacket
although if he meant the values that are in the dir and in the table all you need is to remove the NOT from:
WHERE html NOT IN($files)

Originally posted by vaska
to return values that are IN the dir, but NOT in the table...

Weedpacket

Originally posted by vaska
the problem with array_diff and array_merge/array_unique is that they don't relate the information properly...once they encounter the first instance of a difference they lose control and then begin outputting completely the wrong results (i've posted about this before)...

Could you give a link? I don't see what the problem would be, unless it has something to do with what you do with the list once you've got it, in which case I don't see how getting the same list some other way would help.

i think doing it completely with a mysql query makes the most sense, but HOW is the question...

The problem with using a query to get a list of files that are not in the table (regardless of where else they might be) is that - by definition - they're not in the table in the first place; so how is the query to get them out?

vaska

hey weedy...

i've already broken things down so i can't really show a link...let me try to explain a little...maybe with some illustration...

using array diff...

dir

1.html
2.html
3.html
4.html

table

1.html
3.html
4.html

results

2.html
3.html
4.html

what i should get

2.html

(AFTER array diff finds it's first instance of something that works for the situation...then it breaks down...it seems to work only for the first thing it finds that solves the problem...then it doesn't make the relations and outputs everything)...

one of the BIG problems is that while we can order the results from the table query, how do we sort the results from the dir? i think i had a way of doing this earlier, but things still were not working.

i've tried using array merge with array unique and i got almost the EXACTLY same results...

if somebody has this working i'd love to see what they are doing...but i've gone full circle on this now and both times arrived at the same conclusions (although i'm not claiming to be any kind of an expert on this)...

thanks!...jv

Weedpacket

Well this works for me:

$dir = array('1.html','2.html','3.html','4.html');
$table = array('1.html','4.html','3.html');
$diff = array_diff($dir, $table);
var_dump($diff);

Note that the elements of the two arrays are not in the same order. var_dump() the two lists, and their difference.

As for sorting the results from the directory, [man]sort[/man] should be fine.

Oh, and I found the threads.

vaska

it's nice to see that it is possible...here's the code as it is right now...i'm getting an error:

Warning: Argument #2 to array_diff() is not an array in /pathto/file.php on line 30

$files=array();
$handle=opendir('.') or die("Cannot Open Dir");
while($file=readdir($handle)) {
if($file != "." && $file != "..") {

$files[]="$file";
}
}

$result = mysql_query('SELECT DISTINCT html FROM temp2');

while($row=mysql_fetch_array($result))
{ $files_in_table = $row['html'];
}

////// this is line 30 below

$wanted_files = array_diff($files, $files_in_table);

Code_guy

to make an array to should be:
$files_in_table[] = $row['html'];

otherwise you just get the last $row['html']

vaska

thanks very much...it works!

now i just gotta loop and move on to the next problem i'm trying to solve...