in reply to Re^3: non aliased default var $_
in thread non aliased default var $_

> But then, that makes me wonder why you are seeking an alternative to it?

I'm meditating more about orthogonal code than speed.

But you are really measuring strange things on your sytsem 

lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my
+ @bla=@a; tr/h//d for @bla;print time-$t; <>'
2.48298692703247
lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my
+ @bla= map{tr/h//d; $_} @{\@a};print time-$t; <>'
7.50910615921021
lanx@ubuntu:~$ perl -MTime::HiRes=time -e'my @a= 0..1e6;my $t= time;my
+ @bla= map{tr/h//d; $_}map{$_} @a;print time-$t; <>'
8.25657296180725

[download]

Cheers Rolf

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Re^5: non aliased default var $_
by BrowserUk (Patriarch) on Mar 10, 2010 at 13:46 UTC
    you are really measuring strange things on your sytsem

    Yeah :( It seems to the result of a conflict between 64-bit perl 5.10, and the MS runtime. I get a much smaller differential with 32-bit 5.8.8, but it's still not great: 

    C:\test>\perl32\bin\perl -MTime::HiRes=time -we"my@a=0..1e6;my$t=time;
+my@bla=@a; tr[0][]d for @bla;print time-$t; <>"
0.638000011444092

C:\test>\perl32\bin\perl -MTime::HiRes=time -we"my@a=0..1e6;my$t=time;
+my@bla=map{tr/h//d;$_}map{$_}@a;print time-$t; <>"
9.05199980735779

    [download]

    But every test I tried using malloc()/free() from the 64-bit MS runtime using C seem to fly. Course, it'd be easier to track down if you could get some feedback on these issues, but that's never forthcoming.

    Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
    "Science is about questioning the status quo. Questioning authority".
    In the absence of evidence, opinion is indistinguishable from prejudice.
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In Section Meditations