根据Perl中的哈希值打印密钥

Question

I need to print keys based on vales in hash. Here is the code, I wrote

foreach $value (values %hash)
{
    print "$value\t$hash{$value}\n";
}

Error: I can only print values, but not keys.

Any help will be greatly appreciated.

Thanks

Answer 1

Hashes are designed to be accessed by key, not by value. You need to loop over a list of keys, not values.

Then you can use the keys to access the associated values.

foreach my $key (keys %hash) {
    my $value = $hash{$key};
    say "$key = \t$value";
}

Answer 2

print "$_\t$hash{$_}\n" for keys %hash;

Answer 3

Try with:

for my $key (keys %hash) {
    print "$key\t$hash{$key}\n";
}

Answer 4

一内胆：

map { print "$_\t$hash{$_}\n" } keys %hash;

Answer 5

I would probably use while and each if you want to iterate through keys and values:

while (my ($key, $value) = each %hash) {
    say "$key -> $value";
}

Answer 6

if you want to access it by values, then define your hash as

$x = {  'x1' => [ 'one','x1']}   


foreach ( values %$x ) 
{                                                                                     
     foreach $m1 (@$_) { 
        print "$m1\n";
     }
}     

Notice you can get the key from value by second member of the value array.

Answer 7

The title requests to print key based on the value.

if your key and value in your harsh table should be one to one

foreach $key (keys %hash)
{
  $r_hash{$hash{$key}}=$key;
}
....