my $x = int($str+0);

##</code><code>##

my @test = qw(in inf info information INF INFO Na Nan Nanny NAN NANNY nan04);
foreach my $x (@test) {
  my $y = int($x);
  printf "%11s -> %s\n", $x, $y;
}

##</code><code>##

         in -> 0
        inf -> Inf
       info -> Inf
information -> Inf
        INF -> Inf
       INFO -> Inf
         Na -> 0
        Nan -> NaN
      Nanny -> NaN
        NAN -> NaN
      NANNY -> NaN
      nan04 -> NaN