Beefy Boxes and Bandwidth Generously Provided by pair Networks
Pathologically Eclectic Rubbish Lister
 
PerlMonks  

Re^2: How to test for empty hash? (updated)

by AnomalousMonk (Bishop)
on Aug 08, 2021 at 03:24 UTC ( #11135679=note: print w/replies, xml ) Need Help??


in reply to Re: How to test for empty hash?
in thread How to test for empty hash?

No cause for pause. undef is promoted to the empty string, used as a hash key and assigned undef as its value because that's the default value of items in the empty list | used by Perl when a key in a hash assignment list has no corresponding value, or Odd number of elements in hash assignment.

Win8 Strawberry 5.8.9.5 (32) Sat 08/07/2021 23:15:45 C:\@Work\Perl\monks >perl use strict; use warnings; use Data::Dump qw(dd); my %h = undef; print scalar %h, "\n"; dd \%h; ^Z Odd number of elements in hash assignment at - line 7. Use of uninitialized value in list assignment at - line 7. 1/8 { "" => undef }
The hash ends up with 1 key/value pair.

Update: Clarified (I hope!) the explanation of odd-item hash assignment.


Give a man a fish:  <%-{-{-{-<

Log In?
Username:
Password:

What's my password?
Create A New User
Domain Nodelet?
Node Status?
node history
Node Type: note [id://11135679]
help
Chatterbox?
and the web crawler heard nothing...

How do I use this? | Other CB clients
Other Users?
Others rifling through the Monastery: (5)
As of 2022-01-24 13:01 GMT
Sections?
Information?
Find Nodes?
Leftovers?
    Voting Booth?
    In 2022, my preferred method to securely store passwords is:












    Results (64 votes). Check out past polls.

    Notices?