String comparison

[lilly07]

I have a string with some special characters as below:

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]

I have a string with some special characters as below:

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.

$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:

$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.

if($v eq $v[0]) {
          $ID = $k;
        }

Thanks and Regards

[KevinADC]

Try chomping LIST1 before putting it into a hash:

 while(<LIST1>) {
   chomp;
   ($var1,$var2) = split (/\t/,$_);
   $hash{$var1} = $var2
 }

[KevinADC]

and instead of a while loop use a foreach loop:

       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:

while (<LIST2>) {

and NOT

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:

## for LIST1
$var2 =~ s/^\s*//;      $var2 =~ s/\s*$//;
$hash{$var1} = $var2 ;


###for LIST2
 my @v = split((/\s*\t\s*/,$_);