Re: PerlCritic, $

I never thought about these side effects and I'm glad I looked into this node. Each time I'm here I learn something new & valuable. Thanks to all of you!

But to say something in regards to the code example: Now that I know of the problems using this kind of trimming in map, what do you think about this alternative?

my @files =  map { /^\s*(\S.*?)\s*$/ && $1 || "" } <$FILES>;
[download]

s$$([},&%#}/&/]+}%&{})*;#$&&s&&$^X.($'^"%]=\&(|?*{%
+.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e

Comment on Re: PerlCritic, $_ and map Select or Download Code

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Re^2: PerlCritic, $_ and map by ikegami (Patriarch) on Feb 12, 2009 at 23:00 UTC
`/^\s(\S.?)\s$/ && $1 \|\| ""` is an odd way of writing `/^\s(\S.?)\s$/ ? $1 : ""` If you remove the unnecessary `\S`, you get a pattern that always matches so `/^\s(.?)\s$/ ? $1 : ""` can be simplified to `/^\s(.?)\s$/; $1`	[reply] [d/l] [select]
Re^2: PerlCritic, $_ and map by JavaFan (Canon) on Feb 13, 2009 at 08:31 UTC
what do you think about this alternative? `my @files = map { /^\s(\S.?)\s$/ && $1 \|\| "" } <$FILES>;` [download] Quite bad actually. `s/^\s+//; s/\s+$//;` is common idiom enough that people instantly see what is being done (it is for instance mentioned in the perlfaq) - your solution requires more thinking to see what it does. And then there's performance. `use Benchmark 'cmpthese'; our @data = ('foo', 'foo bar', ' foo', 'foo ', ' foo ', ' foo bar '); + cmpthese -1, { faq => 'for my $x (@::data) {$_ = $x; s/^\s+//; s/\s+$//}', Skeeve => 'for my $x (@::data) {$_ = $x; $_ = /^\s(\S.?)\s$/ && $ +1 \|\| ""}' }; __END__ Rate Skeeve faq Skeeve 19139/s -- -68% faq 59077/s 209% --` [download]	[reply] [d/l] [select]
Re^3: PerlCritic, $_ and map by Skeeve (Parson) on Feb 13, 2009 at 16:06 UTC
While I agree about the benchmark result, I don't agree with what you call "Skeeve's". Try this: `use Benchmark 'cmpthese'; our @data = ('foo', 'foo bar', ' foo', 'foo ', ' foo ', ' foo bar '); + cmpthese -1, { faq => 'my @f= map {local $_ = $_; s/^\s+//; s/\s+$//; $_ } @::da +ta', Skeeve => 'my @f= map { /^\s(\S.?)\s$/ && $1 \|\| "" } @::data', ikegami => 'my @f= map { /^\s(.?)\s$/; $1; } @::data' }; __END__ Rate Skeeve ikegami faq Skeeve 24561/s -- -8% -28% ikegami 26614/s 8% -- -22% faq 33998/s 38% 28% --` [download] `s$$([},&%#}/&/]+}%&{});#$&&s&&$^X.($'^"%]=\&(\|?{%` `+`.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e	[reply] [d/l] [select]