if(('$checkvalue' gt '$value1') &&
       ('$checkvalue' le '$value2'))
    {
        print "$checkvalue $value1 $value2\n";

    }
[download]

    if(($checkvalue > $value1) &&
       ($checkvalue <= $value2))
    {
        print "$checkvalue $value1 $value2\n";

    }
[download]

Update: As VSarkiss (below) and Aviator (in /msg) have correctly pointed out, the bigger issue wasn't that the OP was using the string-wise comparisons (though that was still a problem), but that the OP was comparing the variable names, not that variable values - due to the single-quotes.

gt and le are string-wise comparisons. > and <= are numeric comparisons.

True statement, and a correct fix, but you should also point out that the OP is comparing the variable names as strings rather than their values. (There are single quotes around the vars....)

Do not rebuke them with harsh words ... but rather lead them gently - with URLs - so that they may learn wisdom.

The following implementation assumes that you only provide one parameter on the command line^* - hence you don't have to handle the open. Also, you don't need to fill an array and analyse it later - do it immediately if you can, you'll save memory and time.

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

while (<>) {
   chomp(); # Remove trailing newline
   my $checkvalue = substr($_, 0, 6);
   print("$checkvalue -130 -125\n")
      if ($checkvalue > -130 && $checkvalue <= -125);
}
__END__
~> cat input.txt
-123
-124
-125
-126
-127
-128
-129
-130
-131
-132
~> ./prova.pl input.txt
-125 -130 -125
-126 -130 -125
-127 -130 -125
-128 -130 -125
-129 -130 -125
[download]

*As blazar correctly points out in the subthread, it actually means that this assumes all arguments on the cmd line are files to be processed, so it works perfectly if you want to analyse more files at once.

The following implementation assumes that you only provide one parameter on the command line

(Only a minor side note to your excellent post, but) no, it doesn't!

Well... it doesn't but it can.

The OP only opened the first file for getting input, and it could imply that other parameters on the command line could be used for other reasons. OTOH, my implementation reads from all "files" in the command line, not only the first one.

Of course this is a subtlety in the particular case, but I hope know that everyone here always strives to post as little code as possible to explain h(er|is) problem, and using my solution inside a more elaborate enviroment requires some kind of attention.

Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))')

Don't fool yourself.

my $input = $ARGV[0];

my $count = -127.5;
my $value1 = $count - 2.5;
my $value2 = $count + 2.5;

open(INPUT, "$input") || die "Oops!: Can't open file: $!\n";
while (<INPUT>) {
    my $checkvalue = substr($_, 0, 6);
    print "$checkvalue $value1 $value2\n" if $checkvalue > $value1 and
+ $checkvalue <= $value2;
}
[download]

#!/usr/bin/perl

use strict;

use warnings;
[download]

my $input = $ARGV[0];

open(INPUT, "$input") || die "Oops!: Can't open file: $!\n";

my @inputfile = <INPUT>;

for(my $j = 0; $j < @inputfile; $j++)
[download]

1. avoid slurping in files in list context, if possible,
2. to use perl-like for loops rather than C ones.

Also, nothing wrong with the above logic, per se, but what about a simple

while (<>) {
# ...    
}
[download]

Update:

I have a text file which is nothing more than a list of numbers. I would like to print these numbers if they are between -130 and -125 in value. Unfortunately my current code is not working ... it's printing out all the values in the text file regardless of whether they are between -130 and -125 or not.

#!/usr/bin/perl -ln

use strict;
use warnings;

print if -130 < $_ and $_ < -125;

__END__
[download]

I'm sorry, but I have no idea what this is Blazar. Thanks for the suggestion though.

In turn I have no idea "what this is" is.

Update: I can understand that the OP may have wanted to downvote this, but I don't think it's pointless to complain about badly written posts. For it's not a good practice to post a comment to a whole node without quoting the exact part of it the cmt itself refers to. When it's not obvious, that is - and here it seems to me it is not, by any means. YMMD

The input file was just a text file like this for example

234
654
123
975
[download]

If the input is that simple, why the substr then?

    # Inside the loop...
    my $checkvalue = substr($_, 0, 6);
[download]

If your input is really that simple, don't calculate $checvalue and use $_ directly, possibly after chomping it.

Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))')

Don't fool yourself.

#!/usr/bin/perl

use strict;
use warnings;
my $input = $ARGV[0];
open(INPUT, "<$input") || die "Oops!: Can't open file: $!\n";
while (<INPUT>) {
  chomp
    if (($_>-130)&&($_<=-125)){
      print "$_ -130 -125\n";
    }
}
close (INPUT);
[download]

Well, as someone else noticed, you're comparing some fixed strings that have nothing to do with the $checkvalue, $value1 and $value2 variables. I hadn't even noticed for it's particularly byzantine. Using double quotes would have given you a wrong result. Using single quotes gives you a doubly (or better: multiply!) wrong result!!

You have:

    if(('$checkvalue' gt '$value1') &&
       ('$checkvalue' le '$value2'))
[download]

Make that:

if( $checkvalue > $value1 and
    $checkvalue <= $value2)
[download]

You could try pasting in a bit of your data, just incase we're missing something important.

Re perl-like for loops you should check perlsyn. However, briefly, they're

for (@list) { do_something }
[download]

or

for my $item (@list) { do_something }
[download]

Now it seems to me others already answered most of your other questions. Only thing to add: "OP" stands for either "Original Poster" or "Original Post", depending on the context. Well, that's how I have always understood it...

op is, I guess, that author's abbrv. (heh) for operator. UPDATE: wrong, at least I wrote guess.

Loading a file into an array will consume at least as much memory as the file size, so not much point if you just need to read one line at a time in order.

The reputation relates to perlmonks self moderation, have a read in the FAQ's under experience points.

BTW. Have you got it working yet? Are you going to post some data, or just keep us guessing? ;-)

OP usually stands for "Original Post" or "Original Poster", depending on the context. See also "What does SoPW mean?" Your Guide to Perl Monks Abbreviations.

Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))')

Don't fool yourself.

OP: Original Post(er)

---

The Perfect is the Enemy of the Good.