G'day semipro,

You really need to show your code (i.e. how you're using the value in a calculation), the output you get as well as any error or warning messages (these need to be exactly as you see them and marked up within <code>...</code> tags). Please read the "How do I post a question effectively?" guidelines for full details regarding this.

I suspect the message you're getting is something like:

Argument "$VAR1 = '-39.99994';\n" isn't numeric ...
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The part that isn't numeric is:

$VAR1 = '-39.99994';\n
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This is the string that Dumper($items[-1]) would be returning: '-39.99994' is just part of that string.

I think you should spend some time reading the Data::Dumper documentation. I suspect you haven't quite understood what it does. A more usual usage would be something like:

print Dumper \%some_hash;
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There'll be many examples in the monastery (use Super Search). Here's a couple from recent nodes I've written: hashref data structure dump and arrayref data structure dump.

Perl will happily convert numbers between string and numeric contexts. For example, this code:

#!/usr/bin/env perl -l

use strict;
use warnings;

my $val = '-39.9999400000';
print $val;
print 2.5 * $val;

my $val2 = -39.9999400000;
print $val2;
print "Number in a string >>> $val2 <<<";
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produces this output:

-39.9999400000
-99.99985
-39.99994
Number in a string >>> -39.99994 <<<
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You'll notice that trailing zeros were truncated. You can control the format with sprintf.

You can also force the context yourself: 0+$x (numeric); ''.$x (string); !!$x (boolean).