Re: Counting the number of items returned by split without using a named array

Another way that avoids a named array.

$entries = @{[ split /\s+/ ]};
[download]

Also, split /\s+/ is the similar to as the slightly magical split ' ', except undefs from leading whitespace are suppressed.

In turn, split ' ' is the same as split with no arguments, so you could reduce your code to:

$entries = @{[ split ]};
[download]

If you don't have leading whitespace, or don't want to count the undef any leading whitespace would produce as an entry.

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Comment on Re: Counting the number of items returned by split without using a named array Select or Download Code

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Re^2: Counting the number of items returned by split without using a named array by Anonymous Monk on May 03, 2006 at 13:34 UTC
My bias goes towards either `$entries = @{[ split ]};` [download] or `$entries = () = /\S+/g;` [download] as "most elegant". It's both sufficiently short, although I'm not sure which one is easier to understand for the uninitiated reader :) Just out of curiosity (it doesnt really matter in my case): which one would be the more (CPU- and memory-) efficient one? I.	[reply] [d/l] [select]
Re^3: Counting the number of items returned by split without using a named array by BrowserUk (Patriarch) on May 03, 2006 at 14:08 UTC
`C:\test>p1 our $s = join ' ', 'aa'..'zz';; cmpthese -3, { split => q[ $_=$s; my $n = @{[ split ]}; ], regex => q[ $_=$s; my $n = () = /\S+/g; ] };; Rate regex split regex 546/s -- -50% split 1102/s 102% --` [download] Assuming I didn't goof on the benchmark split appears to be quicker. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal? "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice.	[reply] [d/l]
Re^4: Counting the number of items returned by split without using a named array by Anonymous Monk on May 03, 2006 at 15:16 UTC
Strange perhaps it depends on the length of the input string? My attempt shows a different result You seem to be under windows - so just for comparison: `$ cat a.pl; echo '-----------' ;echo;./a.pl #!/usr/local/bin/perl -w use Benchmark qw(:all) ; our $s = join ' ', 'aa'..'zz';; cmpthese( -3, { split => q[ $_=$s; my $n = @{[ split ]}; ], regex => q[ $_=$s; my $n = () = /\S+/g; ] }); ----------- Rate regex split regex 981/s -- -53% split 2098/s 114% --` [download] Hm, now where's the big diff to the other Bench? I.	[reply] [d/l]
Re^5: Counting the number of items returned by split without using a named array by BrowserUk (Patriarch) on May 03, 2006 at 16:34 UTC
Re^6: Counting the number of items returned by split without using a named array by Anonymous Monk on May 03, 2006 at 17:32 UTC
Re^5: Counting the number of items returned by split without using a named array by Anonymous Monk on May 03, 2006 at 15:20 UTC
Re^3: Counting the number of items returned by split without using a named array by blazar (Canon) on May 03, 2006 at 13:42 UTC
Just out of curiosity (it doesnt really matter in my case): which one would be the more (CPU- and memory-) efficient one? It hardly ever matters. As a wild guess I would say that since the former involves doing something and then undoing it and that something is taking a reference, it is more computationally intensive. In case of doubt `use Benchmark;` [download] I may well (and happily!) prove wrong...	[reply] [d/l]
Re^4: Counting the number of items returned by split without using a named array by Anonymous Monk on May 03, 2006 at 15:02 UTC
As you wish (or not): $ cat foo.pl ; echo "--------";echo; ./foo.pl #!/usr/bin/perl ################## use Benchmark qw(:all) ; sub test1(){ $entries = @{[ split ]}; } sub test2(){ $entries = () = /\S+/g; } $_="This is an example string with several words bla bla bla\n"; $count=1E+7; timethis ($count, "test1()"); print "------------\n"; timethis ($count, "test2()"); -------- timethis 10000000: 13 wallclock secs (12.37 usr + 0.01 sys = 12.38 CP +U) @ 807754.44/s (n=10000000) ------------ timethis 10000000: 7 wallclock secs ( 6.66 usr + 0.00 sys = 6.66 CP +U) @ 1501501.50/s (n=10000000) [download]	[reply] [d/l]
Re^5: Counting the number of items returned by split without using a named array by blazar (Canon) on May 04, 2006 at 10:49 UTC
Re^2: Counting the number of items returned by split without using a named array by blazar (Canon) on May 03, 2006 at 10:57 UTC
No need to reference-dereference: see the last suggestion in Re^3: Counting the number of items returned by split without using a named array. If only I had thought of it earlier... well, it has been extremely interesing to learn that the `=()=` trick wouldn't work with split anyway...	[reply] [d/l]


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