Shouldn't this sort be simple?

Unimatic1140 has asked for the wisdom of the Perl Monks concerning the following question:

Hi everyone, I've been working on this all day and have yet figured out the right syntax. I'm selecting data from a database and placing it into a hash. I want to print the post numbers sometimes in ascending order and other times descending order. I got the ascending part down fine, but for the life of me I cannot figure out how to sort it descending. The code to get the data into a hash and sort it ascending is this:

##SELECT DATA FROM DATABASE AND FILL IT INTO A HASH
$sth = $dbh->prepare("SELECT * FROM $table_POSTS WHERE Thread = '$Sent
+Thread'");
$sth->execute();
$sth->bind_columns(\$THREADd, \$POSTd, \$FORUMd, \$USERNAMEd, \$CREATE
+Dd, \$REPLIEDd, \$TITLEd,\$DRIFTd, \$LINKd, \$JPEGd, \$COMMENTSd, \$I
+Pd, \$REMd, \$OFFENSIVEd );

while($sth->fetch()) {
$view{$POSTd} = { 'thread' => $THREADd,
                    'post' => $POSTd,
                    'forum' => $FORUMd,
                    'username' => $USERNAMEd,
                    'created' => $CREATEDd,
                    'replied' => $REPLIEDd,
                    'title' => $TITLEd,
                    'drift' => $DRIFTd,
                    'link' => $LINKd,
                    'jpeg' => $JPEGd,
                    'comments' => $COMMENTSd,
                    'ip' => $IPd,
                    'rem' => $REMd,
                    'offensive' => $OFFENSIVEd 
};




###PRINT THE POST NUMBERS ASCENDING
foreach $view2 ( sort keys %view ) {

$POST = $view{$view2}->{'post'};

print "$POST<br>";


}
[download]

Can anyone show me how to sort this descending? Big thanks in advance.

Comment on Shouldn't this sort be simple? Download Code

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Re: Shouldn't this sort be simple? by almut (Canon) on Mar 03, 2010 at 22:37 UTC
`foreach $view2 ( sort {$b cmp $a} keys %view ) {` [download] `sort` without an explicit sort routine is the same as `sort {$a cmp $b} ...`. Swapping `$a` and `$b` reverses the outcome of the individual pairwise comparisons, and thus also the ordering of the result.	[reply] [d/l] [select]
Re^2: Shouldn't this sort be simple? by Unimatic1140 (Novice) on Mar 03, 2010 at 22:52 UTC
YAY, thank you almut, that worked perfectly, I was searching the internet all day long and could find the answer. I knew it had to be simple. Thanks again!	[reply]
Re: Shouldn't this sort be simple? by ww (Archbishop) on Mar 03, 2010 at 22:49 UTC
Among other possibilities: href://?node_id=3989;BIT=sort%20descending Re: sorting in hashes hash sorting Re: Reverse sort array ... and, of course, `perldoc -f sort`	[reply] [d/l]
Re: Shouldn't this sort be simple? by jrsimmon (Hermit) on Mar 03, 2010 at 22:39 UTC
Not elegant, but you get the idea... ##SELECT DATA FROM DATABASE AND FILL IT INTO A HASH $sth = $dbh->prepare("SELECT * FROM $table_POSTS WHERE Thread = '$Sent +Thread'"); $sth->execute(); $sth->bind_columns(\$THREADd, \$POSTd, \$FORUMd, \$USERNAMEd, \$CREATE +Dd, \$REPLIEDd, \$TITLEd,\$DRIFTd, \$LINKd, \$JPEGd, \$COMMENTSd, \$I +Pd, \$REMd, \$OFFENSIVEd ); while($sth->fetch()) { $view{$POSTd} = { 'thread' => $THREADd, 'post' => $POSTd, 'forum' => $FORUMd, 'username' => $USERNAMEd, 'created' => $CREATEDd, 'replied' => $REPLIEDd, 'title' => $TITLEd, 'drift' => $DRIFTd, 'link' => $LINKd, 'jpeg' => $JPEGd, 'comments' => $COMMENTSd, 'ip' => $IPd, 'rem' => $REMd, 'offensive' => $OFFENSIVEd }; my @array1; my @array2; ###PRINT THE POST NUMBERS ASCENDING foreach $view2 ( sort keys %view ) { #$POST = $view{$view2}->{'post'}; push @array1, $view{$view2}->{'post'}; unshift @array2, $view{$view2}->{'post'}; #print "$POST<br>"; } foreach my $value (@array1){ print "$value<br>"; } foreach my $value (@array2){ print "$value<br>"; } [download]	[reply] [d/l]