question about algorithm

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

i have a file like

1300018   a1
1300019   a1
1300100   a2
1300101   a2
1300126   a2
1300127   a2
1300128   a2
1300129   a2
1300130   a3
1300131   a3
1300132   a3
1300133   a3
[download]

i want it to be like

i know i should use hash to deal with it... but after completed to assign key and value to hash....how to unique a1 column and make uniqued a1 column to corresponding to fist column?

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Re: question about algorithm by ikegami (Patriarch) on Jul 23, 2009 at 03:47 UTC
Assuming the data is sorted as shown, there's no need for a hash. You just have to keep track of the value from the previous row. `my $prev; while (<$fh>) { my ($field1, $field2) = split; if (!defined($prev) \|\| $prev ne $field2) { print("\n") if !defined($prev); $prev = $field2; print("$field2\n"); } print("$field1\n"); }` [download]	[reply] [d/l]
Re: question about algorithm by jwkrahn (Abbot) on Jul 23, 2009 at 04:31 UTC
`$ echo "1300018 a1 1300019 a1 1300100 a2 1300101 a2 1300126 a2 1300127 a2 1300128 a2 1300129 a2 1300130 a3 1300131 a3 1300132 a3 1300133 a3" \| perl -lane' push @order, $F[ 1 ] unless $h{ $F[ 1 ] }; push @{ $h{ $F[ 1 ] } }, "$F[ 0 ]\n" }{ print "$_ " . @{ $h{ $_ } } . "file\n", @{ $h{ $_ } } for @order ' a1 2file 1300018 1300019 a2 6file 1300100 1300101 1300126 1300127 1300128 1300129 a3 4file 1300130 1300131 1300132 1300133` [download]	[reply] [d/l]
Re: question about algorithm by bichonfrise74 (Vicar) on Jul 23, 2009 at 04:49 UTC
Try this. `#!/usr/bin/perl use strict; my %record; while (<DATA>) { my ($key, $val) = split /\s+/; push( @{ $record{$val} }, $key ); } for my $i ( sort keys %record ) { print "\n\n$i " . scalar @{ $record{$i} } . "file\n" . join "\n", @{ $record{$i} }; } __DATA__ 1300018 a1 1300019 a1 1300100 a2 1300101 a2 1300126 a2 1300127 a2 1300128 a2 1300129 a2 1300130 a3 1300131 a3 1300132 a3 1300133 a3` [download]	[reply] [d/l]
Re: question about algorithm by Corion (Patriarch) on Jul 23, 2009 at 06:27 UTC
Also see part - split up files according to column value, which uses a hash. But it only uses a hash because it cannot assume that the file will be sorted according to the column in question.	[reply]
Re: question about algorithm by perlplayer (Sexton) on Jul 23, 2009 at 11:38 UTC
how about this sollution open FH1, "</users/mhalder/testrun/datafile"; foreach $line (<FH1>){ $line=~s/\s+/:/g; ($fileid,$tag)=split (/\:/,$line); if (defined $filelist->{$tag}){ $filelist->{$tag}->{COUNT}++; $filelist->{$tag}->{FILES}->[($filelist->{$tag}->{COUNT})-1]= +$fileid; } else{ $filelist->{$tag}->{COUNT}=1; $filelist->{$tag}->{FILES}->[($filelist->{$tag}->{COUNT})-1]=$ +fileid; } } print " ** OUTPUT ** \n\n"; foreach $filetag ( sort keys %$filelist){ print "\n$filetag: $filelist->{$filetag}->{'COUNT'} FILES\n\n"; print "LIST OF FILES:\n"; foreach $filename ( @{$filelist->{$filetag}->{FILES}}){ print " $filename\n"; } print; } [download] in my code "datafile" holds the lines 1300018 a1 1300019 a1 1300100 a2 1300101 a2 1300126 a2 1300127 a2 1300128 a2 1300129 a2 1300130 a3 1300131 a3 1300132 a3 1300133 a3	[reply] [d/l]