在 Perl 中遍历多维散列 [英] Traversing a multi-dimensional hash in Perl

问题描述

如果您在 perl 中有一个具有多个维度的散列(或对散列的引用)，并且您想遍历所有值，那么最好的方法是什么.换句话说，如果我们有$f->{$x}{$y}，我想要类似

If you have a hash (or reference to a hash) in perl with many dimensions and you want to iterate across all values, what's the best way to do it. In other words, if we have $f->{$x}{$y}, I want something like

foreach ($x, $y) (deep_keys %{$f})
{
}

代替

foreach $x (keys %f) 
    {
    foreach $y (keys %{$f->{$x}) 
    {
    }
}

推荐答案

这是一个选项.这适用于任意深度的散列:

Here's an option. This works for arbitrarily deep hashes:

sub deep_keys_foreach
{
    my ($hashref, $code, $args) = @_;

    while (my ($k, $v) = each(%$hashref)) {
        my @newargs = defined($args) ? @$args : ();
        push(@newargs, $k);
        if (ref($v) eq 'HASH') {
            deep_keys_foreach($v, $code, \@newargs);
        }
        else {
            $code->(@newargs);
        }
    }
}

deep_keys_foreach($f, sub {
    my ($k1, $k2) = @_;
    print "inside deep_keys, k1=$k1, k2=$k2\n";
});

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