1. Different minimal lengths of region codes
  2. Different maximum lengths of region codes
  3. It sholud find those values on it's own
 Update But... it's all there already ?
There are no string comparisons, and the order of look-ups assures that the longest existent key/prefix always win.

Oh, it's not, I just misunderstood your points. But definitely not hard to add, if really needed:
use List::Util;

my $min_prefix_length = min keys %prefixes;
my $max_prefix_length = max keys %prefixes;

my $prefix_length = $max_prefix_length;

while ( $prefix_length-- >= $min_prefix_length) { 
    last if exists $prefixes{ substr( $phone, 0, $prefix_length) };
} 

# Error/inexistent prefix if $prefix_length < $min_prefix_length;

[download]
etc.

Krambambuli
---

In reply to Re^5: (german) region code detection - request for thoughts by Krambambuli
in thread (german) region code detection - request for thoughts by Skeeve

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