String comparison

lilly07

I have a string with some special characters as below:

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chr1:52055616-52061682

If I have to compare two strings in the above format, do I have to use regex because normal $string1 eq $string2 does not work.

Thanks.

KevinADC

Quote:

Originally Posted by lilly07

I have a string with some special characters as below:

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chr1:52055616-52061682

If I have to compare two strings in the above format, do I have to use regex because normal $string1 eq $string2 does not work.

Thanks.

Show some more code or the context you are using it because string comparison will work.

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 $str1 = 'chr1:52055616-52061682';

$str2 = 'chr1:52055616-52061682';

if ($str1 eq $str2) {

   print "They are equal";

}

lilly07

Hi Kelvin,
Thanks for your response.
Yes you are right. It was not due to the string comparison problem.

I have a set of keys and values in a hash and I am trying to search for the cooresponding key with getting value from the other file. And I am trying as below:

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$hashfile = $ARGV[0];

open (LIST1,$hashfile) || die "FILE not found\n";

while(<LIST1>) {

  ($var1,$var2) = split (/\t/,$_);

  $hash{$var1} = $var2

}

close(LIST1);
 
$datafile = $ARGV[1];

 open (LIST2,$datafile) || die "FILE not found\n";

while(<LIST1>) {

chomp $_;

  my @v = split((/\t/,$_);

      while(($k,$v) = each %hash) {

       if($v eq $v[0]) {

          $ID = $k;

        }

       }

 print "$ID\t$_\n";

}

But getting the key from hash using $v[0] never works. Please lte me know whether my approach has any problem.

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if($v eq $v[0]) {

          $ID = $k;

        }

Thanks and Regards

KevinADC

Try chomping LIST1 before putting it into a hash:

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  while(<LIST1>) {

   chomp;

   ($var1,$var2) = split (/\t/,$_);

   $hash{$var1} = $var2

 }

KevinADC

and instead of a while loop use a foreach loop:

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        foreach my $key (keys %hash) {

        if($hash{$key} eq $v[0]) {

           $ID = $key;

           last;#<--get out as soon as possible

         }

     }

lilly07

Thanks Kelvin. I also tried using the above steps.

RonB

Are there any duplicated values in the hash?

If so then how do you want to determine which key to use for the $ID? If not, then it would be more efficient to reverse the hash and use 'exists' instead of the foreach loop.

nithinpes

From your description, I believe you are trying to compare values in second file with the hash value read from first file. In that case, the second while loop should be:

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while (<LIST2>) {

and NOT

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while (<LIST1>) {

If that was just a typo while posting and not the actual problem you are facing, Kevin's code should work for you.
Else, probably there may be accidentally included trailing/leading spaces for the values (apart from the tab delimitation).
Try removing them:

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## for LIST1

$var2 =~ s/^\s*//;      $var2 =~ s/\s*$//;

$hash{$var1} = $var2 ;
 
###for LIST2

 my @v = split((/\s*\t\s*/,$_);

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