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Re: list context (iterators)

by LanX (Canon)
on Dec 07, 2010 at 00:12 UTC ( #875713=note: print w/ replies, xml ) Need Help??


in reply to list context

in my $x = 10; the = is a scalar assignment which returns the assigned scalar

in my ($y) = 10; the = is a list assignment which returns the number of assigned elementsą

That's a crucial trick for iterators, where returned elements might be false (like 0 , '' or undef).

So

while ( ($x) = iterator() ) { ... }
will work as long as anything (i.e. no empty list) is returned, while
while ( $x = iterator() ) { ... }
can break if you don't use special magics like "0 but true".

Cheers Rolf

UPDATE:

1) in scalar context!


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