如何在 Perl hash 中将字符串转换为浮点数？

Question

My motive is to convert the string number into floating point number while creating a hash.

I have placed my entire code and error below. Please help me to solve this issue.

Sample code

use strict;
use warnings;

use Data::Dumper;

my $price = 8.5;

my $g={};
$g->{'get'}=sprintf('%.02f',$price);

print Dumper($g);

Current output

$VAR1 = {
          'get' => '8.50'
        };

Expected output

$VAR1 = {
          'get' => 8.50
        };

Answer 1

Despite the single quotes around 8.50 in the Dumper output, Perl will still treat it as a numeric value when you go to use it:

use strict;
use warnings;

my $price = 8.5;

my $g={};
$g->{'get'}=sprintf('%.02f',$price);

my $x = 5;
printf "%.02f\n", $x + $g->{get};

Outputs:

13.50

Answer 2

use Scalar::Util 'looks_like_number';
.
.
print Dumper($g) =~ s/'(.*?)'/looks_like_number($1)?$1:"'$1'"/ger;

Which changes the output from Dumper before it's printed. It removes both ' s of every single quoted string if it looks like a number according to Scalar::Util.

Answer 3

I suspect you're worrying unnecessarily here. Perl treats strings and numbers as largely interchangeable and will generally do the right thing with data of either type. The number of times when you should care if you have a string or a number is tiny.

In fact, even if you explicitly give Perl a number in code like yours, it will be displayed as a string:

$ perl -MData::Dumper -E'say Dumper { get => 8.5 }'
$VAR1 = {
          'get' => '8.5'
        };