![3
delete(@a[0..$#a]);](https://image.slidesharecdn.com/clean-array-100626081851-phpapp02/85/How-to-clean-an-array-15-320.jpg)
![use Benchmark qw(:all :hireswallclock);
my $size = 1000; Be
cmpthese timethese -3, { nc
'@a = ...' => sub { my @a = (('test')x$size); h m
return; }, ar
'undef @a' => sub { my @a = (('test')x$size); undef @a; ke
return; }, d
'@a=()' => sub { my @a = (('test')x$size); @a = ();
return; },
'splice @a' => sub { my @a = (('test')x$size); splice @a;
return; },
'$#a = -1' => sub { my @a = (('test')x$size); $#a = -1;
return; },
'shift @a while @a' => sub { my @a = (('test')x$size); shift @a
while @a; return; },
'delete @a[0..#$a]' => sub { my @a = (('test')x$size);
delete(@a[0..$#a]); return; },
};
при $size=1000;
shift @a while @a 2642/s -- -22% -44%
-44% -45% -45% -45%
delete @a[0..#$a] 3376/s 28% -- -28%
-29% -29% -30% -30%
splice @a 4722/s 79% 40% --
-0% -1% -2% -2%](https://image.slidesharecdn.com/clean-array-100626081851-phpapp02/85/How-to-clean-an-array-33-320.jpg)
How to clean an array
- 1. How to clean an array
- 4. as a Perl developer
- 5. Good programmer writes good code in every language
- 6. But lots of fun
- 7. sub clear{ my $template = shift @args; @{$self->{tokens}} = (); foreach (map {$_->{name}} @{$template->{si}}){ while (my $r = shift @{$self->{$_}->{res}}){} } }
- 8. Wat de fuck is dat?
- 9. sub clear{ my $template = shift @args; @{$self->{tokens}} = (); foreach (map {$_->{name}} @{$template->{si}}){ while (my $r = shift @{$self->{$_}->{res}}){} } } A subroutine to make an object empty
- 10. sub clear{ my $template = shift @args; @{$self->{tokens}} = (); foreach (map {$_->{name}} @{$template->{si}}){ while (my $r = shift @{$self->{$_}->{res}}){} } } Note this
- 11. Posted that piece to Moscow.pm mailing list
- 12. And we bacame crazy
- 13. 1 while (my $r = shift @a) {}
- 14. 2 splice @a;
- 16. 4 grep {shift @a} @a;
- 17. 5 @a = ();
- 19. 6 undef @a;
- 20. ccn@ccn-laptop ~ $ perl -le 'my @a=(1,2,3); while(my $r = shift @a){}; print @a' ccn@ccn-laptop ~ $ perl -le 'my @a=(0,1,2,3); while(my $r = shift @a){}; print @a' 123
- 21. 7 while(defined(my $r = shift @a)) {}
- 22. ccn@ccn-laptop ~ $ perl -le 'my @a=(undef,1,2,3);while (defined(my $r=shift @a)){};print @a' 123
- 23. Doesn’t work
- 24. Let’s make it useful
- 25. $str = "abcc{0}def"; @a = split //, $str; $c++ while(shift @a); say $c - 1; Calculate zero-ending string length
- 28. 10 shift @a while @a; Much better!
- 29. 11 shift @a while @a and die;
- 30. 12 shift @a while scalar @a;
- 31. 13 $#a = -1 Who remembers?!
- 32. Bonus my @a = qw(oh eh); while (push(@a, shift @a)) {}; Endless sex loop
- 33. use Benchmark qw(:all :hireswallclock); my $size = 1000; Be cmpthese timethese -3, { nc '@a = ...' => sub { my @a = (('test')x$size); h m return; }, ar 'undef @a' => sub { my @a = (('test')x$size); undef @a; ke return; }, d '@a=()' => sub { my @a = (('test')x$size); @a = (); return; }, 'splice @a' => sub { my @a = (('test')x$size); splice @a; return; }, '$#a = -1' => sub { my @a = (('test')x$size); $#a = -1; return; }, 'shift @a while @a' => sub { my @a = (('test')x$size); shift @a while @a; return; }, 'delete @a[0..#$a]' => sub { my @a = (('test')x$size); delete(@a[0..$#a]); return; }, }; при $size=1000; shift @a while @a 2642/s -- -22% -44% -44% -45% -45% -45% delete @a[0..#$a] 3376/s 28% -- -28% -29% -29% -30% -30% splice @a 4722/s 79% 40% -- -0% -1% -2% -2%
- 34. TIMTOWTDI or die; Andrew Shitov talks.shitov.ru | [email protected]