Alan M. Carroll wrote:
I went netsearching for this but couldn't find anything in all the noise.
1) What is the runtime cost of the scalar operator? Is it constant or does it
depend on the size of the array? Is it different than $#array?
2) What's the best way to turn the result of the map function into an array
reference? Say one has an array of objects and one wants an array reference to
an array of object IDs. Should I do
A) my @ids = map $_->id, @objs; my $ref = [EMAIL PROTECTED];
B) my $ref = [ map $_->id, @objs ];
C) my $ref = \map $_->id, @objs;
3) Does the answer to (2) depend on which list generating function is called?
Thanks!
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Since you've already received the answer to the everything except the
runtime cost, I'll try to answer that. According to perlguts, the
length of an array is not calculated until the first time it's asked
for, after which it's stored. I could be wrong, but according to that,
the first time it's called it's a O(n) counting operation and after that
it's a constant access.
Oh, and for part 2, I'd go with A, for a map, grep, whatever, for
readability.
Sorry for any formatting problems: my mail client has decided to have a
mind of it's own.
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