Reverse Sorting in Perl

dave123 posted this at 21:12 — 14th March 2000.

They have: 4 posts

Joined: Mar 2000

I am trying to reverse sort a flat-file, pipe delimited database so that I can display records in descending order. I need to sort the records by ID number and the ID number is the first field in my database file. (Ex. ID|Title|Image|Message) Any help would be greatly appreciated. I will probably have to use the reverse sort function in Perl, but I'm not sure how do it so that it will sort one database file based on a numeric field value.

Thanks,
Dave

Orpheus posted this at 21:53 — 14th March 2000.

They have: 568 posts

Joined: Nov 1999

I believe I have something for you.

code:

for my $x (0..scalar(@array)) {
   $id[$x] .= "|" . $rest[$x];
}

@sorted =
map { join "|", @$_ }
sort { $b->[1] <=> $a->[1] }
map { [ split /\|/ ] }
@array; 
[/code]

you may have to change the code around a little but you get the ideas....

Rob Pengelly posted this at 23:31 — 14th March 2000.

They have: 850 posts

Joined: Jul 1999

So if it had

That doesn't seem hard, just try:

code:

open(IN,"<IN.txt");
@arr = <IN>;
close(IN)

@arr = sort @arr;
@arr = reverse @arr;

open(IN,">IN.txt");
print IN @arr;
close(IN);
[/code]


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Termites eat through wood two times faster when listening to rock music.

[This message has been edited by robp (edited 14 March 2000).]

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Orpheus posted this at 00:04 — 15th March 2000.

They have: 568 posts

Joined: Nov 1999

Robp That would work fine but what if he's going to have more than 9 entries into the database?

Remember sort will work but it will only sort by the first number of every line.

So if he had 1 15 25 12 it would sort it as
1 15 12 25... and thats not good

Orpheus posted this at 00:15 — 15th March 2000.

They have: 568 posts

Joined: Nov 1999

Robp Would you be willing to help me out with my web site? i.e. make scripts and tutorials. I've seen a ton of your postings around the forum and you seem to be as knowledgable (if not more) about perl as me.

Want to help out?
email me [email protected] (nice email isn't it

dave123 posted this at 05:47 — 15th March 2000.

They have: 4 posts

Joined: Mar 2000

Do you know how I can modify the code to handle the sorting of numeric values above 9?

Rob Pengelly posted this at 14:18 — 15th March 2000.

They have: 850 posts

Joined: Jul 1999

@arr = sort {$b <=> $a} @arr;

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Termites eat through wood two times faster when listening to rock music.