Hans Ginzel wrote:
Hello!
Hello,
Is there a shorter way to write $a = ! $a, please?
Something analogous to ++ and -- operators like $a !! or !! $a would negate
the variable $a and return its previous or new value respectively.
You can do that if you use a reference to a scalar like this:
$ perl -le'my $x = do { \vec my $y, 0, 1 }; for ( 1 .. 6 ) { print ++$$x }'
1
0
1
0
1
0
$ perl -le'my $x = do { \vec my $y, 0, 1 }; for ( 1 .. 6 ) { print --$$x }'
1
0
1
0
1
0
$ perl -le'my $x = do { \vec my $y, 0, 1 }; for ( 1 .. 6 ) { print $$x++ }'
0
1
0
1
0
1
$ perl -le'my $x = do { \vec my $y, 0, 1 }; for ( 1 .. 6 ) { print $$x-- }'
0
1
0
1
0
1
I used the do {} block so that $y doesn't leak out into the rest of the
program, but you can omit it if you want.
John
--
Any intelligent fool can make things bigger and
more complex... It takes a touch of genius -
and a lot of courage to move in the opposite
direction. -- Albert Einstein
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