Re^2: Truth and Falsehood

Logically, operators like grep, map, m//, and s/// all return false by returning an empty list, at least in a simple description.

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Re^3: Truth and Falsehood by ikegami (Patriarch) on Aug 30, 2019 at 16:31 UTC
That makes no sense. An empty list isn't false. Or true. It's not a scalar, so those concepts don't apply to it. You can't evaluate whether an empty list is true or false. You can only evaluate if a scalar is true or false. As such, if you're trying to get a true or false value from those operators, you would be evaluating them in scalar context, and the following is what the listed operators actually return in scalar context: `grep` returns the count of matching elements. `map` returns the count of elements it would return. m// and s/// return success or not.	[reply] [d/l] [select]

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Re^3: Truth and Falsehood
by ikegami (Patriarch) on Aug 30, 2019 at 16:31 UTC

That makes no sense. An empty list isn't false. Or true. It's not a scalar, so those concepts don't apply to it. You can't evaluate whether an empty list is true or false. You can only evaluate if a scalar is true or false.

As such, if you're trying to get a true or false value from those operators, you would be evaluating them in scalar context, and the following is what the listed operators actually return in scalar context:

grep returns the count of matching elements.
map returns the count of elements it would return.
m// and s/// return success or not.

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