issues with array_diff, array_merge, array_unique

vaska

ok...i'm trying to read the files from a directory, pass these to an array ($files) and compare these to what is in the database (temp)...i want it to return ONLY the values that ARE NOT in the db...

so...if xyz.html is in the directory and not in the db it would be output...

it seems that array_diff is the way to go, but i also tried array_merge with array_unique and got basically the same results...

i think i've diagnosed the problem...the array from the directory does not sort the files in any particular way...so when it compares them to the query from the db only the first or sometimes the second values are calculated properly...then it's so completely out of order it just doesn't work (i spent some time adding and deleting from the db to test this out)...

now...anybody have any thoughts about how to resolve this? can i somehow ORDER my $files array from the directory?

this is my code...it's doing it's job...but i'm missing out on the ordering part of things...if anybody has any other means or methods to try please advise...

thanks...jv

////dbconnectinfo...

$sql = "SELECT * FROM temp2 ORDER BY html ASC";
$result = mysql_query ($sql) or DIE ("Unexpected Erro for MySQL Database" .mysql_error());
$rows = mysql_fetch_array ($result);

$handle = opendir('.') OR DIE ("can not open dir");
while ($file = readdir ($handle)) {
if ($file != "." && $file != "..") {
$files[] = $file;
}
}
$myArr = array_diff ($files, $rows);

this could be also (but i think array_diff is the way to go overall):
$myArr = array_merge ($files, $rows);
$myArr = array_unique ($myArr);

for ($i=0; $i<count($myArr); $i++) {
print $myArr[$i];
}
closedir ($handle);
?>

xblue

Hi Vaska,

mysql_fetch_array only returns one row each time it is called (always the next one), may that be the problem?

If you want to get all rows into an array, you could use:

while ($row = mysql_fetch_array ($result)) {
    $rows[] = $row['column_name'];
}

that would put all values from the desired column into the array $rows.

Hope this helps!

vaska

yeah...thanks...

i'm getting just crazy results now (although it's clearly doing more work)...

61.html and 63.html won't show up...they aren't the db...

12.html shows up if 61.html is in the directory...but not otherwise...

1024.html doesn't show up...it's not in the db either...

but things that are IN the db...definitely do not show up in the results...so now it's just a matter of figuring out why the things in the dir are acting so strange...

i played with array_multisort, but i don't really think it's necessary...

any ideas?

thanks...jv

xblue

Hi,

it's not easy to tell what's going wrong remotely.

However, another idea that might even be more efficient: have mysql do the work for you.

I'd use the file to create a list with all unwanted entries. they should be as following:

$list="'value1', 'value2', 'value3', ..."; (note the single quotes)

Then, use this list in your query to select all entries that are not in the list:

$sql="SELECT * FROM table_name WHERE column_name NOT IN ($list)";
mysql_query($sql);
(note that the variable holding the list must be in parenthesis)

You'd access the entries in a while loop as before, but already filtered.

If things should still go wrong, for debugging it might be helpful to print the list and the sql query and the mysql error (if any).

vaska

per your instructions...i'm trying to do it that way...i'm gettin an "unexpected error" message at this line ->

$query = mysql_query ("SELECT * FROM temp2 WHERE html NOT IN ($files) " )

full code...

<?
$handle=opendir('.') or die("Cannot Open Dir");
while ($file=readdir($handle)) {
if ($file != "." && $file != "..") {
$files[]='$file';
}
}
///////// dbconnectinfo

$query = mysql_query ("SELECT * FROM temp2 WHERE html NOT IN ($files) " ) or die ("Unexpected error for MySQL database [3b]");
$row = mysql_fetch_array($query);
while ($row = mysql_fetch_array ($result)) {
$rows[] = $row['html'];
}
closedir($handle);
?>

xblue

From what your script looks like, I don't think $files is a string (not an array) with all the values in single quotes, comma-separated.

Again, I recommend to print the mysql_error and the complete query to track down what's going wrong.