Re: Sorting with perl

[RMGir]

(Edit: See Sorting with perl for a reformatted version of the question, and other answers).

I'm going to try to answer your question, but it would have been easier if you'd used the <code> and a few <p>aragraph tags to make it more readable. Please check out Writeup Formatting Tips.

1st file has words that are in specific order like this: (not alphabetic) GAVSTE GAVARC GAVADA GAVIMM GAVSP

So you open up the first file, and read it into a hash that defines the sort order: (I'm assuming there's newlines between the words in the first file)

#/usr/bin/perl -w

use strict;

my %sortOrder;

# replace "file1" with the filename of the first file
my $currentOrder=0;

open(FILE1,"<file1") or die "Can't open 'file1', error $!";
while(<FILE1>) {
    chomp;
    # associate the current word with its place in the sort order
    $sortOrder{$_}=$currentOrder++;     
}

close(FILE1);

It is "order quide" for sorting 2nd file in flatfile (delimiter is "|"): GAVARC 10.3. Tahkoluoto 1m SOMMOL 10.3. Tahkoluoto 7m GAVSTE 7.4. Preiviiki 1p GAVARC 7.4. Preiviiki 2p SOMMOL 16.3. Kallo 6m

I have to guess at where the newlines are, so I'm going to assume the 2nd file looks like:

GAVARC|10.3.|Tahkoluoto|1m
SOMMOL|10.3.|Tahkoluoto|7m
GAVSTE|7.4.|Preiviiki|1p
GAVARC|7.4.|Preiviiki|2p
SOMMOL|16.3.|Kallo|6m

(continued from previous code:)

my @data;

open(FILE2,"<file2") or die "Can't open 'file2', error $!";

while(<FILE2>) {
    chomp;
    my ($keyField)=split /\|/,$_;
    die "Don't have a sort key for $keyField" unless exists $sortOrder
+{$keyField};
    # push in a reference to an array where the first 
    # element is the sort order.  This is the Scwartzian 
    # transform sorting method
    push @data,[$sortOrder{$keyField},$_];
}

close(FILE2);

my @sorted=map {pop @$_}
           sort {$a->[0] <=> $b->[0]}
           @data;

# I'm assuming you want the | delimiters in the output?
print join "\n", @sorted;

For more details see Schwartzian Transform. A higher performance approach is the Guttman Rosler Transform but it's a bit more complicated to follow.
--
Mike