Play golf on an array of hashrefs

very empty has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks,
I have an array of hashrefs. Each hash has a key "mykey". Now would like to know if there is a one-line-way to get an array consisting of all values at this common key.

foreach $elem (@array) {
    push @myvalues, $$elem{"mykey"};
}
[download]

should do what I want, but @myvalues is an auxiliary variable I do not want to introduce.

Regards...

Comment on Play golf on an array of hashrefs Select or Download Code

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Re: Play golf on an array of hashrefs by Abigail-II (Bishop) on Jun 10, 2002 at 15:37 UTC
`map {$_ -> {mykey}} @array` [download] Abigail	[reply] [d/l]
Re: Play golf on an array of hashrefs by Joost (Canon) on Jun 10, 2002 at 15:36 UTC
`@array = map { exists $_->{mykey} ? $_->{mykey} : () } @array;` [download] Update: this also checks for existence of the key, if you don't need to, go for Abigail's solution. `-- Joost downtime n. The period during which a system is error-free and immune from user input.` [download]	[reply] [d/l] [select]
Re: Play golf on an array of hashrefs by frankus (Priest) on Jun 10, 2002 at 15:38 UTC
`my @myvalues = map {$$elem{mykey} } @array;` [download] -- Brother Frankus. ¤	[reply] [d/l]
Re: Re: Play golf on an array of hashrefs by mephit (Scribe) on Jun 10, 2002 at 21:37 UTC
Actually, the use of $elem in the map won't work, as the OP used $elem as the "alias" variable in the foreach loop. There is no alias in this map. `$> perl -e '@array=({mykey=>foo}, {mykey=>bar}), @out = map{ $$elem{my +key} } @array; print @out;' $>` [download] Use $_ instead, as Joost or Abigail suggested. -- There are 10 kinds of people -- those that understand binary, and those that don't.	[reply] [d/l]