problem in looping

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

open FILE1,"1.txt" or die "can't open file 1";
open FILE2,"2.txt" or die "can't open file 2";
open(w1,">3.txt");
open(w2,">4.txt");
while (my $line1 = <FILE1>) {
chomp $line1;
my @cond1 = split("\t" , $line1);
print "$cond1[2]\n";
while (my $line2 = <FILE2>) {
chomp $line2;
my @cond2 = split("\t" , $line2);
print "$cond2[2]\n";
if(abs($cond1[2]-$cond2[2])>=2)
{
print w1 "$line1\n";
print w2 "$line2\n";
}
}
}
close FILE1;
close FILE2;
close w1;
close w2;
[download]

i just want to open 2 files and find difference between cond12 and cond22 and if the difference is greater than or equal to some number say 2 print the lines again in 2 different files.

file 1 (1.txt) 
aqw dfr 34 
poilo ggg 98 
file 2  (2.txt)
qww asd 28 
poilo ggg 97
[download]

when i try this i am not able to get the output in proper way i mean my output should look like this

3.txt 
aqw dfr 34
4.txt 
qww asd 28
[download]

it would not print the other lines since the difference is less than 2

Comment on problem in looping Select or Download Code

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Re: problem in looping by kcott (Archbishop) on Aug 13, 2012 at 19:35 UTC
If you want to compare those files line-by-line, you should lose the second `while`, i.e. `while (my $line2 = <FILE2>) {` [download] should just be `my $line2 = <FILE2>;` [download] and, of course, remove the closing brace from the second `while` block. With your code as it is now, you're comparing: 34 with 28 (diff > 2); then 34 with 97 (diff > 2); then 98 with nothing! - you've read all of `2.txt` by this point. I'd also recommend you take a look at the syntax shown in the first two example statements in the documentation for open. -- Ken	[reply] [d/l] [select]
Re: problem in looping by hbm (Hermit) on Aug 13, 2012 at 19:10 UTC
This should get you close, though it assumes the two input files have the same number of lines. `use strict; use warnings; my @f1 = get_lines("1.txt"); my @f2 = get_lines("2.txt"); open(my $out1, ">", "3.txt") or die; open(my $out2, ">", "4.txt") or die; for my $i (0..$#f1){ if (abs($f1[$i]->[1]-$f2[$i]->[1])>1){ print $out1 "$f1[$i]->[0]\n"; print $out2 "$f2[$i]->[0]\n"; } } close $out1; close $out2; sub get_lines { my $file = shift; my @lines; open(my $fh, "<", $file) or die("Unable to open $file: $!"); while(<$fh>){ chomp; /(\d+)$/; push @lines, [ $_, $1 ]; } close $fh; return @lines; }` [download]	[reply] [d/l]
Re: problem in looping by aitap (Curate) on Aug 13, 2012 at 23:35 UTC
First of all, use warnings and strict if your script is longer than several lines. It is really a good practice which will help you to avoid many errors. Secondly, it is recommended to use more modern and more safe three-argument form of open, using scalar variables as filehandles: `open my $file1,"<","1.txt" or die "1.txt: $!\n"; open my $file2,"<","2.txt" or die "2.txt: $!\n"; open my $w1,">","3.txt" or die "3.txt: $!\n"; open my $w2,">","4.txt" or die "4.txt: $!\n";` [download] You can even use autodie to skip writing those checks. You can also pass file names as command-line arguments. Thirdly, you can process both files in one `while` loop, if you want to just check the data of the same line numbers: `while ( defined(my $line1=<$file1>) and defined(my $line2=<$file2>) ) { if (abs( (split"\t",$line1)[2]-(split"\t",$line2)[2] )>=2) { print $w1 "$line1\n"; print $w2 "$line2\n"; } }` [download] Fourthly, remember: indenting is your friend. It helps to understand the structure if your program. Run your code through Perl::Tidy, set up your editor to indent the text for you, or install the Perl IDE. Note: the code samples are untested and may fail for some reason. Sorry if my advice was wrong.	[reply] [d/l] [select]