Something eq hashref key

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

Is there a way to have a conditional equating to the keys of a hashref?

my $fields = {
    'field1' => {
         'maxlength' => 20,
    },
    'field2' => {
         'maxlength' => 100,
    },

};
# something like this

if ('field1' eq "key of $fields") {
    # do something
}
[download]

Without looping over the hashref.

Does that make sense?

Thank you in advance.

Comment on Something eq hashref key Download Code

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Re: Something eq hashref key by haukex (Archbishop) on Mar 25, 2019 at 13:44 UTC
I'm not sure I fully understand your question, maybe you could provide a few more examples of what should be true and what should be false, but are you perhaps looking for exists? As in: `if ( exists $fields->{field1} )`	[reply] [d/l]
Re^2: Something eq hashref key by LanX (Saint) on Mar 25, 2019 at 14:06 UTC
On a side note, it's a pity we can't use exists on hash slices ... `DB<9> exists @h{"a","z"} exists argument is not a HASH or ARRAY element or a subroutine at (eva +l 18)...` [download] Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply] [d/l]
Re^3: Something eq hashref key by hdb (Monsignor) on Mar 25, 2019 at 14:17 UTC
In a recent thread it was shown that hash slices are not faster than maps, `exists` on hash slices is not needed. `sub slex { my $h = shift; return map { exists $h->{$_} \|\| 0 } @_ } my %h = map { $_ => 1 } 'a'..'t'; my @bool = slex \%h, 'a'..'z'; print "@bool\n";` [download]	[reply] [d/l] [select]
Re^4: Something eq hashref key by LanX (Saint) on Mar 25, 2019 at 14:59 UTC
Re^2: Something eq hashref key by Anonymous Monk on Mar 25, 2019 at 13:51 UTC
Thank you so much, haukex. Yes, "exists" is what I was looking for. Thank you for the enlightenment :))	[reply]