How to use foreach with a hash reference

Question

I have this code  foreach my  key  keys  ad grp           Do something     which works   How would the same look like  if I don t have  ad grp  but a reference   ad grp ref  to the hash

User · Answer

In Perl 5 14  it works in now in Perl 5 13   we ll be able to just use keys on the hash reference  use v5 13 7   foreach my  key  keys  ad grp ref

User · Answer

As others have stated  you have to dereference the reference  The keys function requires that its argument starts with a     My preference   foreach my  key  keys    ad grp ref       According to Conway   foreach my  key  keys     ad grp ref        Guess who you should listen to     You might want to read through the Perl Reference Documentation    If you find yourself doing a lot of stuff with references to hashes and hashes of lists and lists of hashes  you might want to start thinking about using Object Oriented Perl  There s a lot of nice little tutorials in the Perl documentation

User · Answer

foreach my  key  keys   ad grp ref                Perl  Critic and daxim recommend the style  foreach my  key  keys     ad grp ref                  out of concerns for readability and maintenance  so that you don t need to think hard about what to change when you need to use     ad grp obj 3 - gt get ref     instead of     ad grp ref

User · Answer

So  with Perl 5 20  the new answer is   foreach my  key  keys  ad grp ref- gt          which has the advantage of transparently working with more complicated expressions   foreach my  key  keys  ad grp obj 3 - gt get ref  - gt         etc    See perlref for the full documentation   Note  in Perl version 5 20 and 5 22  this syntax is considered experimental  so you need  use feature  postderef   no warnings  experimental  postderef     at the top of any file that uses it   Perl 5 24 and later don t require any pragmas for this feature

[perl] How to use foreach with a hash reference?

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