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Re: hash or nest loop
by zejames (Hermit) on Sep 20, 2004 at 13:40 UTC
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Hum... Sounds like homework to me. It would be better if you provided your code...
open F, "file1" or die "Problem with file1";
open G, "file2" or die "Problem with file2";
@file1 = map { (split /\s+/, $_)[0]; } <F>;
@file2 = map { (split /\s+/, $_)[0]; } <G>;
while ($coord2 = shift @file2) {
$coord1 = shift @file1;
push @result, $coord1 - $coord2;
unshift @file1, $coord1;
}
open H, "> result.txt" or die "Unable to open result.txt";
print H join ("\n", @result);
Warning : this code is untested.
update : changed a indice error : 2 -> 0. Now the code is tested.
HTH
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[d/l] |
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trying to pick up perl while studying in the field of bioinformatics
thanks though u've helped me getting started!
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Re: hash or nest loop
by Limbic~Region (Chancellor) on Sep 20, 2004 at 14:47 UTC
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Anonymous Monk,
Sometimes a problem just needs to be solved quickly and all that matters is getting the result (throw away code). Here is some code that might help get a feel for how quickly you can solve problems with Perl.
#!/usr/bin/perl
use strict;
use warnings;
open (FILE1, '<', 'file1.txt') or die $!;
open (FILE2, '<', 'file2.txt') or die $!;
open (FILE3, '>', 'file3.txt') or die $!;
my ($X) = <FILE1> =~ /^(\d+)/;
print FILE3 $X - $_, "\n" for map { /^(\d+)/ } <FILE2>;
Of course, memory constraints may mean that this isn't feasible and more thought has to go into it and might end up not being throw-away.
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[d/l] |
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damn sweet. Those few lines made my day today (at least thus far -- its only noon here). Sheer elegance.
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Re: hash or nest loop
by doowah2004 (Monk) on Sep 20, 2004 at 13:47 UTC
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I am sure that a lot of people can offer a better, cleaner and more efficient solution, but a couple of simple loops should do the trick.
open (FILE1, "<$file1");
@lines1 = <FILE1>;
close (FILE1);
open (FILE2, "<$file2");
@lines2 = <FILE1>;
close (FILE1);
open (FILE3, ">$file3");
foreach $line1(@lines1) {
chomp $line1;
($x1,$y1,$z1) = split (/ /,$line1);
foreach $line2(@lines2) {
chomp $line2;
($x2,$y2,$z2) = split (/ /,$line2);
print FILE3 $x1 - $x2 . "\n";
}
}
close (FILE3);
This code is not tested, and lacks the appropriate my,our... but it should give you a good idea of one method to tackle the problem.
Cameron
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[d/l] |
Re: hash or nest loop
by dragonchild (Archbishop) on Sep 20, 2004 at 13:58 UTC
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Your requirements:
I need to take the first x co-ord in file 1, and substract the x value in file 2 from it - repeat for all x values in file 2.
My code:
use strict;
use warnings;
$|++;
use constant X => 0;
use constant Y => 1;
use constant Z => 2;
# take the first x co-ord in file 1
my @f1_coords = do {
my $filename = 'file1';
open( my $fh, "<$filename" )
or die "Cannot open '$filename' for reading: $!\n";
my $line = <$fh>;
close $fh;
split( ' ', $line );
};
# substract the x value in file 2 from it - repeat for all x values in
+ file 2
my $filename = 'file2';
open( my $fh, "<$filename" )
or die "Cannot open '$filename' for reading: $!\n";
my $outname = 'file3';
open( my $out_fh = ">$outname" )
or die "Cannot open '$outname' for writing: $!\n";
while (my $line = <$fh>)
{
my @f2_coords = split( ' ', $line );
print $out_fh $f1_coords[X] - $f2_coords[X], $/;
}
close $out_fh;
close $fh;
You will want to read through my code a few times. It contains a ton of Perl idioms that may help you learn your way. Enjoy!
------
We are the carpenters and bricklayers of the Information Age.
Then there are Damian modules.... *sigh* ... that's not about being less-lazy -- that's about being on some really good drugs -- you know, there is no spoon. - flyingmoose
I shouldn't have to say this, but any code, unless otherwise stated, is untested
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[d/l] |
Re: hash or nest loop
by Jasper (Chaplain) on Sep 20, 2004 at 14:42 UTC
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Seems to me it's much more simple to just (mostly pseudo-code)
# open FILE1 and FILE2
my ($f1, $f2);
while (($f1 = <FILE1>) && ($f2 = <FILE2>) {
# split and subtract and print with $f1 and $f2 as in other suggesti
+ons.
}
# close all.
This way, while you do have two (probably three, with the printing and all) filehandles open, you don't have to slurp any of them. | [reply]
[d/l] |
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Jasper,
I am not sure if you looked at the desired output, but the AM said all the x values from file 2 subtracted from just the first x value in file 1. Your proposed solution would be corresponding x values, which I do not believe is desired.
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but i guess the above is only useful if both files are of same size?
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