The second one allocates a whole array and then throws it away. The first one is handled by perl and may be optimized into something much more efficient than it looks. I would not use the second when the first is available. Incidentally you'll find that the following split// variant 

my $string = "zero   one  two three";
$number = (split /\s+/, $string,3)[1];

[download]

is more efficient. It needs to be 2 more than the index you want access. One more for the 0/1 base correction, and one more so that the index you want doesnt include additional values afterwards.

A benchmark shows that the variant I posted above is around 300% faster than the array variant you posted. 

use Benchmark 'cmpthese';


our $string = "zero   one  two three four five six seven eight nine te
+n";

my $bench={
        list  => '$number = ( split /\\s+/, $string  )  [1]',
        array => '$number = [ split /\\s+/, $string  ]->[1]',
        list3 => '$number = ( split /\\s+/, $string,3)  [1]',
    };

while (my ($key,$expr)=each %$bench) {
    printf "%s : %s\n",$key,eval($expr)||die $@;
}

for my $i (1..3) {
    cmpthese -3,$bench;
    sleep(1);
}
__END__
list : one
list3 : one
array : one
Benchmark: running array, list, list3, each for at least 3 CPU seconds
+...
     array:  3 wallclock secs ( 3.06 usr +  0.00 sys =  3.06 CPU) @ 54
+729.26/s (n=167581)
      list:  2 wallclock secs ( 3.24 usr +  0.00 sys =  3.24 CPU) @ 85
+398.45/s (n=276264)
     list3:  4 wallclock secs ( 3.03 usr +  0.00 sys =  3.03 CPU) @ 22
+4004.62/s (n=679182)
          Rate array  list list3
array  54729/s    --  -36%  -76%
list   85398/s   56%    --  -62%
list3 224005/s  309%  162%    --
Benchmark: running array, list, list3, each for at least 3 CPU seconds
+...
     array:  3 wallclock secs ( 3.11 usr +  0.00 sys =  3.11 CPU) @ 53
+543.26/s (n=166466)
      list:  3 wallclock secs ( 3.25 usr +  0.00 sys =  3.25 CPU) @ 85
+733.23/s (n=278633)
     list3:  4 wallclock secs ( 3.11 usr +  0.00 sys =  3.11 CPU) @ 22
+6976.21/s (n=705896)
          Rate array  list list3
array  53543/s    --  -38%  -76%
list   85733/s   60%    --  -62%
list3 226976/s  324%  165%    --
Benchmark: running array, list, list3, each for at least 3 CPU seconds
+...
     array:  3 wallclock secs ( 3.02 usr +  0.00 sys =  3.02 CPU) @ 55
+106.76/s (n=166202)
      list:  3 wallclock secs ( 3.05 usr +  0.00 sys =  3.05 CPU) @ 84
+117.16/s (n=256305)
     list3:  3 wallclock secs ( 3.14 usr +  0.00 sys =  3.14 CPU) @ 22
+3896.50/s (n=703035)
          Rate array  list list3
array  55107/s    --  -34%  -75%
list   84117/s   53%    --  -62%
list3 223896/s  306%  166%    --

[download]

---
demerphq

<Elian> And I do take a kind of perverse pleasure in having an OO assembly language...

In reply to Re: coding style suggestion by demerphq
in thread coding style suggestion: (...)[1] vs. [...]->[1] by thens

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