There is also a variation on yours; $x &&= 1; and there is the corresponding pair on or; $x = $x || 0; $x ||= 0;. Update: Also trinary, $x = $x ? 1 : 0; and all sorts of variations on that, which have the advantage that truth and falsity are what you say they are.</Update>

None of the basic three are equivalent. Here is a comparison:
Expr Value Result Value Result
$x = $x && 1; true 1 false unchanged
$x = $x || 0; true unchanged false 0
$x = !! $x; true1 false''
But see diotalevi's fine reply for what !! actually returns. Context is everything!
Only $x = !! $x; gives you what I think you want.

But perl generally limps along just fine without any boolean type at all. See What is truth? (Curiosity corner).

After Compline,
Zaxo

In reply to Re: Converting to boolean by Zaxo
in thread Converting to boolean by dragonchild

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