Re^2: Test if a subhash in a referenced hash exists

Moritz, your reply helped me find the problem. After your suggestion did not work either I rechecked the subroutine and found that I had not passed $coordinates into it. Doing so, now your suggestion and my original line both work. Also, I thought about exist, defined and true and think I should use exist, because it is a prerequisite to defined and true. Thanks a lot for your help! Henri

Comment on Re^2: Test if a subhash in a referenced hash exists

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Re^3: Test if a subhash in a referenced hash exists by almut (Canon) on May 28, 2010 at 10:37 UTC
...but note that exists does not test what you asked for in the subject line, i.e. if a subhash exists — it just tests whether the respective hash key exists, or more precisely, whether the respective hash element has ever been initialized (with whatever value, including `undef`). `$data->{foo} = ""; if ( exists $data->{foo} ) { print $data->{foo}{bar}; # 'Can't use string ("") as a HASH ref +...' }` [download] or with `undef` as value (in which case the missing hash would be autovivfied) `$data->{foo} = undef; if ( exists $data->{foo} ) { print $data->{foo}{bar}; # 'Use of uninitialized value in print +...' }` [download]	[reply] [d/l] [select]
Re^4: Test if a subhash in a referenced hash exists by Henri (Novice) on May 29, 2010 at 13:17 UTC
If I understand you right, with “exits” I am testing if keys at the top level of the anonymous subhash exist. If I wanted to test if the hash reference exists I would need to use “ref”. Correct?	[reply]