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Re: How to compare an empty key with another empty key in associative array

by bart (Canon)
on Oct 24, 2012 at 11:06 UTC ( #1000604=note: print w/replies, xml ) Need Help??


in reply to How to compare an empty key with another empty key in associative array

That sounds like you're coming from PHP. Well, OK, I'll write a little utility function empty which should look a bit familiar. That way you can compare if 2 values are both empty.
sub empty { my $r = shift; if(!ref $r) { return !$r } if(ref $r eq 'HASH') { return !keys %$r } if(ref $r eq 'ARRAY') { return !@$r } if(ref $r eq 'SCALAR') { return !$$r } return !1; } $a = ''; $b = {}; $c = []; if(empty($a) && empty($b) && empty($c)) { print "PASS"; }

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[ambrus]: Corion: from the docs, it definitely looks like it would be possible to write an AnyEvent driver for it using Prima::File and Prima::Timer.
[ambrus]: (I haven't found an idle event.)
[ambrus]: However, I also looked at the internals, and found two interesting things:
[marto]: stupid xpath question, I have a xpath copied from the browser, is the * wildcard supposed to work for IDs? e.g. '//*[@id="*"]/ div/div/header/p/a '?
[ambrus]: The main loop for unixish systems is in https://metacpan. org/source/ KARASIK/Prima-1. 49/unix/apc_app.c. It is a hand-rolled select loop, but also always spins at least once every 0.2 seconds for some reason.
[ambrus]: marto: no, not that way. if you just want to test for an existing id attribute, then write *[@id] , or you can match a regexp to the value of that attribute like *[@id=~/something/ ]
[marto]: ambrus, thanks I ended up going with '//*[starts- with(@id, "thread_")]...
[ambrus]: Sometimes it's easier to just match elements in ways other than xpath, like directly with perl code.

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