Re: if not defined

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Re^2: if not defined by bart (Canon) on Mar 23, 2007 at 18:44 UTC
No need to switch to `!`, `not` is legal Perl.	[reply] [d/l] [select]
Re^3: if not defined by ikegami (Patriarch) on Mar 23, 2007 at 19:41 UTC
But there is a precedence problem `if (not defined($pname) && $pname ne '')` means `if (not (defined($pname) && ($pname ne '')))` while `if (!defined($pname) && $pname ne '')` means `if ((!defined($pname)) && ($pname ne ''))` The OP wants `if (!defined($pname) && $pname ne '')` or `if ((not defined($pname)) && $pname ne '')`	[reply] [d/l] [select]
Re^4: if not defined by bart (Canon) on Mar 23, 2007 at 19:47 UTC
No need to use `&&`, as there is `and`. :) Anyway, you've pinpointed the problem, it's a precedence problem, and `if(not foo and not bar) { ...` [download] will do the right thing, as desired.	[reply] [d/l] [select]
Re^4: if not defined by pKai (Priest) on Mar 23, 2007 at 20:51 UTC
The OP wants `if (!defined($pname) && $pname ne '')` really? For one, we have `>perl -w -e "print 1 if !defined($pname) && $pname ne ''" Use of uninitialized value in string ne at -e line 1.` [download] While `not defined($pname) && $pname ne ''` if, and only if `! defined($pname) \|\| $pname eq ''` Which looks perfectly reasonable in a test like `if (!defined($pname) \|\| $pname eq '') { croak 'We want something real in $pname. Not undef or the empty st +ring'; }` [download]	[reply] [d/l] [select]