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Re^5: var comparison

by LanX (Canon)
on Sep 08, 2012 at 18:42 UTC ( #992519=note: print w/ replies, xml ) Need Help??


in reply to Re^4: var comparison
in thread var comparison

hmm, nobody gave you a code example ?

DB<100> @option{qw/a b c/}=() => (undef, undef, undef) DB<101> exists $option{a} => 1 #true DB<102> exists $option{d} => "" #false

but smart-match should be safe as long as you don't forget the quotes.

Cheers Rolf


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Re^6: var comparison
by nemesisgus (Acolyte) on Sep 09, 2012 at 02:03 UTC

    Nice hash slice, thanks!

    Just let me polish up your code so other newbies don't get confused:

    my %option; @option{qw/a b c/}=(); # my %option = ( # 'a' => undef, # 'b' => undef, # 'c' => undef # ); exists $option{a} and print 'true'; exists $option{d} or print 'false';

    PS: what the h**l is DB <...> ?

      DB <...> : the code was run under the debugger. Example of a debugger session:
      $ perl -de 42 Loading DB routines from perl5db.pl version 1.32 Editor support available. Enter h or `h h' for help, or `man perldebug' for more help. main::(-e:1): 42 DB<1> %hash = qw( a 1 b 2 c 3 d 4 ); DB<2> print %hash c3a1b2d4 DB<3> print scalar %hash 4/8 DB<4> $hash{e} = undef DB<5> print scalar %hash 5/8 DB<6> print "true" if defined $hash{e} DB<7> print "true" if exists $hash{e} true DB<8>

        So much to learn... Thank you again!

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