my $size=scalar keys%hash_ref;
 37 print STDERR "top-level hash_ref $size\n";
 38 foreach  my $key (keys %hash_ref)
 39 {
 40     $size=scalar keys%{$hash_ref{$key}};
 41     print STDERR "second-level hash_ref $size\n";
 42
 43 }
 44 foreach my $key (keys %hash_ref)
 45 {
 46     foreach my $subkey (keys %{$hash_ref{$key}})
 47     {
 48         print STDERR "$key\t$subkey\n";
 49
 50     }
 51 }

字符串数组相关:

use strict;
use warnings;
my $asc=ord("我");
my $val=$asc & 0x80;
print "$asc\n";
print "$val\n" ;
my $line="我是中国人";
my $lenline= length $line;
my @vec =split //,$line;
my $size= scalar @vec;
print "字符串的长度是 $lenline 数组的长度为$size\n" ;