我有这样的结构(散列哈希)：
%hash=(
Level1_1=> {
Level2_1 => "val1",Level2_2=> {
Level3_1 => "val2",Level3_2 => "val1",Level3_3 => "val3",},Level2_3 => "val3",Level1_2=> {
Level2_1 => "val1",Level2_2=> {
Level3_1 => "val1",Level3_2 => "val2",Level1_3=> {
Level2_1 => "val1",Level2_2 => "val2",});
我想grep这个由“val2”过滤的嵌套结构
输出应该是：
%result=(
Level1_1=> { Level2_2=> { Level3_1 => "val2"} },Level1_2=> { Level2_2=> { Level3_2 => "val2" } },Level1_3=> { Level2_2 => "val2" }
);
我的第一个想法是使用这样的递归子例程：
hashwalk_v( \%hash );
sub hashwalk_v
{
my ($element,@array) = @_;
if( ref($element) =~ /HASH/ )
{
while (my ($key,$value) = each %$element)
{
if( ref($value) =~ /HASH/ ) {
push (@array,$key);
hashwalk_v($value,@array);
} else {
if ( $value =~ "val2") {
push (@array,$key);
print $_ . "\n" for @array;
} else {
@array ="";
}
}
}
}
}
但不幸的是我无法保存前一个循环中的哈希键.
有任何想法吗？？
解决方法
类似的方法,
use Data::Dumper; print Dumper hfilter(\%hash,"val2");
sub hfilter {
my ($h,$find) = @_;
return if ref $h ne "HASH";
my %ret = map {
my $v = $h->{$_};
my $new = ref($v) && hfilter($v,$find);
$new ? ($_ => $new)
: $v eq $find ? ($_ => $v)
: ();
} keys %$h;
return %ret ? \%ret : ();
}