How can I convert hex strings into numbers in Perl?

Question

I recently wrote a script which parsed a text representation of a single binary byte month field.

(Don't ask :-{ )

After fiddling with sprintf for a while I gave up and did this;

our %months = qw / x01 1 
       x02 2
       x03 3 
       x04 4 
       x05 5 
       x06 6 
       x07 7 
       x08 8 
       x09 9 
       x0a 10 
       x0b 11 
       x0c 12 /;
...
my $month = $months{$text};

Which I get away with, because I'm only using 12 numbers, but is there a better way of doing this?

Solution 1

If you have

$hex_string = "0x10";

you can use:

$hex_val = hex($hex_string);

And you'll get: $hex_val == 16

hex doesn't require the "0x" at the beginning of the string. If it's missing it will still translate a hex string to a number.

You can also use oct to translate binary, octal or hex strings to numbers based on the prefix:

• 0b - binary
• 0 - octal
• 0x - hex

Solution 2

See hex and/or oct.

#!/usr/bin/perl

use strict;
use warnings;

my @months = map hex, qw/x01 x02 x03 x04 x05 x06 x07 x08 x09 x0a x0b x0c/;
print "$_\n" for @months;