Perl_引用

#about ref num

my $num=10;

my $rnum=$num;

$$rnum += 2;

print $$rnum."n";#print 12

${$rnum} += 2;

print ${$rnum}."n";#print 14

my $rdnum=10;

#ref string
my $a="string1";
my $ra=$a;
my $rs="string2";
my @array = (10,20);
my $rarray=@array;
print $$rarray[1]."n";# print 20
print ${$rarray}[1]."n";# print 20
push @$rarray,30;
print $$rarray[2]."n";# print 30
print ${$rarray}[2]."n";# print 30
print $#$rarray."n";# print 2
print $#{$rarray}."n";# print 2

#引用匿名数组

$ra = [ ];
$ra = [1,"hello"];
print ${$ra}[1]."n";#print hello

#ref hash

my %hash =("key1"=>"value1","key2"=>"value2","key3"=>"value3");
my $rhash=%hash;
print $$rhash{"key1"}."n";# print value1
print ${$rhash}{"key1"}."n";# print value1
my @slice=@$rhash{'key1','key2'};# content:i value1,value2

#分割哈希
my @slice1=@{$rhash}{'key1',value2
print $slice[0]."n";#print value1
print $slice1[0]."n";#print value1

#引用匿名哈希
$rhash = {};
$rhash = {"k1","v1","k2","v2"};
print ${$rhash}{"k1"}."n";#print v1
$rhash ={"k3"=>"v3","k4"=>"v4"};
print ${$rhash}{"k3"}."n";#print v1

#引用数组、哈希元素

my $r_array_element=$array[1];
my $r_hash_element=$hash{"key1"};

#嵌套数据结构

my %parent=('name'=>'par','age'=>'50');
my %ch1=('name'=>'tom','age'=>'10');
my %ch2=('name'=>'tim','age'=>'12');
my @children=(%ch1,%ch2);
$parent{'children'}=[%ch1,%ch2];#$parent{'children'}=@children;
print $parent{'children'}->[1]->{'age'}."n";#print child 2,tim's age: 12
print $parent{'children'}[0]{'name'}."n";#print child 1,tom's name: tom
%parent=(); %parent = ( 'name'=>'par','age'=>'50','children'=>[{'name'=>'tom','age'=>10},{'name'=>'tim','age'=>12}] ); print $parent{'children'}->[1]->{'age'}."n";#print child 2,tim's age: 12 print $parent{'children'}[0]{'name'}."n";#print child 1,tom's name: tom print values(%parent);#it's not value