>>>>> "PP" == Philip Potter <philip.g.pot...@gmail.com> writes:
PP> 2009/11/11 Uri Guttman <u...@stemsystems.com>:
>> you can also simplify the copy a little with a hash ref:
>>
>> my $readfsgs_flags = { map { $_ => $flags->{$_} } @flags_to_copy } ;
PP> Is this really simpler than my version?
PP> @readfsgs_fla...@flags_to_copy} = @{$flag...@flags_to_copy};
one less line to declare the hash as mine is a hash ref. fewer lines is
generally simpler (not alway!). also more people get map than slices (i
use them both all the time).
PP> It took me a while to parse the map call, and the extra curlies from
PP> the anonymous hash get confused with the code block curlies. Is this
PP> map call a common technique for constructing subhashes (analogous to
PP> subsets)?
sure. maps can generate any list from an input list. what is different
about a list of key/values to populate a hash? if you don't like the
hash ref style, assign the map to a hash itself:
my %readfsgs_flags = map { $_ => $flags->{$_} } @flags_to_copy ;
i just like the ref style as i don't need to use \%readfsgs_flags to
pass it down the line.
PP> Also, is the hash ref necessary? Would this also work?
PP> my %readfsgs_flags = map { $_ => $flags->{$_} } @flags_to_copy;
>> and if you feel like really combining lines (not so great in this case):
>>
>> my $readfsgs_flags = { map { $_ => $flags->{$_} }
>> grep { exists( $flags->{$_} } qw(limit) ;
>>
>>
>> or another cleaner way would be to put the exists inside the map:
>>
>> my $readfsgs_flags = {
>> map { ( exists( $flags->{$_} ) ? $_ => $flags->{$_} : () }
qw(limit) ;
PP> I see what you've done there. I think you're right that it's probably
PP> best in two statements -- after all, it's going to be two lines
PP> whether it's two statements or one.
sure. i was just showing how to combine lines like that. sometimes there
is a decent win, other times it gets too noisy.
uri
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