Re^5: What esteemed monks think about changes necessary/desirable in Perl 7 outside of OO staff

Please also show the time of just populating the lines with no substitution.

|14:29 choroba@triangle 
|~ $ time perl -e 'for (1..1000000) { $line="   aaa bbb ccc ddd eee ff
+f    ";}'

real    0m0.041s
user    0m0.042s
sys     0m0.000s
|14:29 choroba@triangle 
|~ $ time perl -e 'for (1..1000000) { $line="   aaa bbb ccc ddd eee ff
+f    "; $line =~ s/^ +//; $line =~ s/ +$//;}'

real    0m0.747s
user    0m0.740s
sys     0m0.004s
[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

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Re^6: What esteemed monks think about changes necessary/desirable in Perl 7 outside of OO staff by Tux (Canon) on Sep 15, 2020 at 14:18 UTC
`split` is faster, but also less versatile: `$ perl -MBenchmark=cmpthese -wE'my$x=join" "=>"",("aaa")x5,"";say"s +ourc: \|$x\|";sub splt{split" ",$x,1};sub rgx{$x=~s/^\s+//r};say "split +: \|",splt(),"\|";say"regex: \|",rgx(),"\|";cmpthese(-2,{splt=>\&splt,rgx +=>\&rgx})' sourc: \| aaa aaa aaa aaa aaa \| split: \|aaa aaa aaa aaa aaa \| regex: \|aaa aaa aaa aaa aaa \| Rate rgx splt rgx 3382502/s -- -58% splt 7989872/s 136% --` [download] and `split` is not able to trim trailing space without help `$ perl -MBenchmark=cmpthese -wE'my$x=join" "=>"",("abc")x5,"";say"s +ourc: \|$x\|";sub splt{split" ",reverse((split" ",(reverse$x),1)[0]),1; +};sub rgx{$x=~s/^\s+//r=~s/\s+$//r};say "split: \|",splt(),"\|";say"reg +ex: \|",rgx(),"\|";cmpthese(-2,{splt=>\&splt,rgx=>\&rgx})' sourc: \| abc abc abc abc abc \| split: \|abc abc abc abc abc\| regex: \|abc abc abc abc abc\| Rate rgx splt rgx 1047602/s -- -64% splt 2915089/s 178% --` [download] It is still faster, but I would pity the coder that has to maintain it. So, concluding `split` (as a function) is faster, the next step is to profile your complete process and wonder if winning this little is worth the maintainability nightmare. If this functionality only uses 0.01% of the complete time, I would not even think about bothering. If it makes up 75% of the process time, and you are dealing with 4 Tb datastreams I would create an XS module that does exactly what I need and squeeze every CPU microsecond out of that optimized code. I seriously doubt if that would be worth it. Seriously. There are millions of existing scripts that already use `s{^\s+}{}` and `s{\s+$}{}` (which removes all whitespace, so my functions may not be identical for some data), and people that use Perl, are familiar with it. Introducing functions like `ltrim` and `rtrim` or whatever they are to be called will for sure appeal to many users (unless the syntax is not obvious: as an excercise to the reader, please try to build `split` from scratch and implement all edge cases). Is presented as an XS module, it may be used as playground, but then one has to ask themselves, does the time required to import the module weigh against the time gained in the function? Enjoy, Have FUN! H.Merijn	[reply] [d/l] [select]
Re^6: What esteemed monks think about changes necessary/desirable in Perl 7 outside of OO staff by likbez (Sexton) on Sep 15, 2020 at 12:43 UTC
`[0] # time perl -e 'for (1..1000000) { $line=" aaa bbb ccc ddd eee +fff "; }' real 0m0.140s user 0m0.124s sys 0m0.015s` [download]	[reply] [d/l]


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