CODEWITHSUNDEEP
perlhash
BryanK
BryanK

Reputation: 1231

Check a hash for empty keys, Perl

I have a hash that looks like this

$VAR1 = {
      '' => 0,
      'example' => 17953878,
      'test' => 14504908,
      'arbitrary' => 14977444
};

I am printing the hash with the basic 

for (keys %hash) {
    print "$_ : $hash{$_}";
}

What is the best way to check for the empty key and remove it before printing the hash? Also id like to know how I can check if the key is 'undef' or just an empty string, does it evaluate to false? etc.

Upvotes: 0

Views: 3438

Answers (2)

monoi
monoi

Reputation: 51

If your data is coming from an external source, and you know that empty strings are never valid input, you can just do

delete $hash{''};

before printing.

Upvotes: 3

mpapec
mpapec

Reputation: 50677

for (keys %hash) {
    length  or next;     # key is empty string, skip it
    # $_ eq "" and next; # explicit comparison to ""

    print "$_ : $hash{$_}";
}

Checking with exists, outside of loop:

print "hash has empty string key\n" if exists($hash{""});

Upvotes: 5

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