Scott R. Godin wrote:
> Interesting .. I would have thought that map would be faster, but it
> appears that foreach is, in this instance. curious.. :)
>
>
> 4:52pm {193} localhost:/home/webadmin/>$ perl bench.pl
> Benchmark: running Foreach, Map for at least 5 CPU seconds...
> Foreach: 9 wallclock secs
> ( 5.24 usr + 0.00 sys = 5.24 CPU) @ 35906.30/s (n=188149)
> Map: 11 wallclock secs
> ( 5.29 usr + 0.01 sys = 5.30 CPU) @ 24095.47/s (n=127706)
> 4:54pm {194} localhost:/home/webadmin/>$ cat bench.pl
> #!/usr/bin/perl
>
> use warnings;
> use strict;
>
> use Benchmark qw(timethese);
>
> timethese( -5, {
> "Foreach" => sub {
> my %nr;
> $nr{$_}++ foreach
> qw{ shipto_company shipto_email billto_company
> billto_email same_bill_ship rkh_quantity rkp_quantity rmh_quantity
> rmp_quantity rbh_quantity rbp_quantity ship_on_account
> shipping_id_number order_number };
> },
> "Map" => sub {
> my %nr = map {$_ => 1}
> qw{ shipto_company shipto_email billto_company
> billto_email same_bill_ship rkh_quantity rkp_quantity rmh_quantity
> rmp_quantity rbh_quantity rbp_quantity ship_on_account
> shipping_id_number order_number };
> }, }
> );
To be equivalent the foreach sub should use assignment instead of
postincrement (which is also faster.)
Foreach => sub {
my %nr;
$nr{ $_ } = 1 foreach
qw{ shipto_company shipto_email billto_company
billto_email same_bill_ship rkh_quantity rkp_quantity rmh_quantity
rmp_quantity rbh_quantity rbp_quantity ship_on_account
shipping_id_number order_number };
},
Also in my test using a hash slice is faster still.
Foreach => sub {
my %nr;
$_ = 1 foreach
@nr{ qw{ shipto_company shipto_email billto_company
billto_email same_bill_ship rkh_quantity rkp_quantity rmh_quantity
rmp_quantity rbh_quantity rbp_quantity ship_on_account
shipping_id_number order_number } };
},
John
--
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