if its only about translating a number, than using a hash is by far the best solution

use strict;
use warnings;

my %trans = (1 => "One", 2 => "Two", 3 => "Three");
my $var   = '2.123.45.6';
if ( $var =~ /^(\d)\./ ) {
    print "$var starts with $trans{$1}";
} else {
    print "$var malformed";
}
[download]

Now since this became a general discussion of "switch", for completeness TIMTOWTDI:

use strict;
use warnings;

my $i;
for my $case (1..4) {
    eval { goto "_$case" }    or
      $i = "Other"; next;
  _1: $i = "One"  ; next;
  _2: $i = "Two"  ; next;
  _3: $i = "Three"; next;
} continue {
    print "$case is $i\n";
}
[download]

Hashes with dispatch tables (slow sub calls) and if-elsif-chains (slow linear testing) shouldn't be as fast as this approach.