RE: (tye)RE: The Best Infinite Loop

So I tried it (with Deparse)...

while ()  { $_++; last if $_ == 1000; }
while (1) { $_++; last if $_ == 1000; }
for (;;)  { $_++; last if $_ == 1000; }
[download]

perl -MO=Deparse test.pl

for (;;) {
    ++$_;
    last if $_ == 1000;
}
for (;;) {
    ++$_;
    last if $_ == 1000;
}
for (;;) {
    ++$_;
    last if $_ == 1000;
}
test.pl syntax OK
[download]

So they should be all the same speed. I'm with tye on this one - I'll be sticking with with while(1) since I think it looks nicer.

Have fun,

rdw

Comment on RE: (tye)RE: The Best Infinite Loop Select or Download Code

Replies are listed 'Best First'.

RE: RE: (tye)RE: The Best Infinite Loop
by BlaisePascal (Monk) on Oct 18, 2000 at 02:16 UTC

tye

#!/usr/bin/perl -w

use strict;
use Benchmark;

timethese( 1000, 
  {
   '0while' => sub { $_ = 0; while (1)   { $_++; last if ($_ == 10000)
+; } },
   '0for'   => sub { $_ = 0; for   (;;)  { $_++; last if ($_ == 10000)
+; } },
   '0redo1' => sub { $_ = 0;   { $_++; redo if     ($_ <  10000);     
+  } },
   '0redo2' => sub { $_ = 0;   { $_++; redo unless ($_ == 10000);     
+  } },
   '0redo3' => sub { $_ = 0;   { $_++; last if     ($_ == 10000); redo
+; } },
   '1while' => sub { $_ = 0; while (1)   { $_++; last if ($_ == 10000)
+; } },
   '1for'   => sub { $_ = 0; for   (;;)  { $_++; last if ($_ == 10000)
+; } },
   '1redo1' => sub { $_ = 0;   { $_++; redo if     ($_ <  10000);     
+  } },
   '1redo2' => sub { $_ = 0;   { $_++; redo unless ($_ == 10000);     
+  } },
   '1redo3' => sub { $_ = 0;   { $_++; last if     ($_ == 10000); redo
+; } },
  });
__END__
Benchmark: timing 1000 iterations of 0for, 0redo1, 0redo2, 0redo3, 0wh
+ile, 1for, 1redo1, 1redo2, 1redo3, 1while...
      0for: 14 wallclock secs (11.43 usr +  0.00 sys = 11.43 CPU)
    0redo1: 14 wallclock secs (11.62 usr +  0.00 sys = 11.62 CPU)
    0redo2: 15 wallclock secs (12.68 usr +  0.00 sys = 12.68 CPU)
    0redo3: 15 wallclock secs (12.36 usr +  0.00 sys = 12.36 CPU)
    0while: 14 wallclock secs (11.48 usr +  0.00 sys = 11.48 CPU)
      1for: 13 wallclock secs (11.40 usr +  0.00 sys = 11.40 CPU)
    1redo1: 14 wallclock secs (11.63 usr +  0.00 sys = 11.63 CPU)
    1redo2: 14 wallclock secs (11.54 usr +  0.00 sys = 11.54 CPU)
    1redo3: 15 wallclock secs (12.36 usr +  0.01 sys = 12.37 CPU)
    1while: 14 wallclock secs (11.42 usr +  0.00 sys = 11.42 CPU)
[download]

[reply]
[d/l]


Your skill will accomplish what the force of many cannot
	PerlMonks