how to evaluate exponential notations and floating points

[BhariD]

I have the following code:

while($evalue = <DATA>){
chomp;
   if($evalue < 0.001){
      print OUTPUT $evalue, "\n";
    }
}
close DATA;

DATA
-----------
1e-005
2e-090
0.00
0.67
1.0
4e-065

For some reason the above code does not seem to do what I want. It prints out the input in the DATA as it is without evaluating the if statement above.

OUTPUT (wrong)
-----------
1e-005
2e-090
0.00
0.67
1.0
4e-065

The output should look like this: (the evalue of 0.00 means 1e-180, so should be counted).

OUTPUT (correct)
-----------
1e-005
2e-090
0.00
4e-065

Anyone knows what I am doing wrong here?

[kennethk]

I cannot replicate your problem with the posted code. The following code, taken almost entirely from your OP, works for me:

#!/usr/bin/perl
use strict;
use warnings;

while(my $evalue = <DATA>){
    chomp $evalue;
    if($evalue < 0.001){
        print $evalue, "\n";
    }
}
__DATA__
1e-005
2e-090
0.00
0.67
1.0
4e-065

The main changes are the file handles. Note that your chomp was not given a variable, and hence was operating on $_ instead of $evalue.

[ikegami]

Anyone knows what I am doing wrong here?

Asking questions about one piece of code while posting another.

It doesn't produce the results you describe, and you would have noticed you're chomping the wrong variable.

while($evalue = <DATA>){
chomp;                        # Should be chomp( $evalue );
   if($evalue < 0.001){
      print $evalue, "\n";
    }
}
close DATA;

__DATA__
1e-005
2e-090
0.00
0.67
1.0
4e-065

1e-005

2e-090

0.00

4e-065

[GrandFather]

Always use strictures (use strict; use warnings; - see The strictures, according to Seuss).

Providing a stand alone script that reproduces the error helps a lot too. In this case something like the following (although this sample doesn't demonstrate your issue):

use strict;
use warnings;

while (my $evalue = <DATA>) {
    chomp $evalue;
    if ($evalue < 0.001) {
        print $evalue, "\n";
    }
}

__DATA__
1e-005
2e-090
0.00
0.67
1.0
4e-065

[bichonfrise74]

Take a look at this.

#!/usr/bin/perl

use strict;

while( my $evalue = <DATA> ){
    chomp $evalue;
    if($evalue < 0.001){
        print "$evalue\n";
    }
}

__DATA__
1e-005
2e-090
0.00
0.67
1.0
4e-065