Re^2: regexp find last word

Basically the same principle as my answer, but slightly slower.

use Benchmark;

print "holli\n";
timethis (999999, sub { $_ = "fox comes and fox goes into forest"; s/(
+fox.+)(fox.+?forest)/${1}the $2/; });
print "borisz\n";
timethis (999999, sub { $_ = "fox comes and fox goes into forest"; s/(
+.*)(fox.+?forest)/$1the $2/; });
print "sh1tn\n";
timethis (999999, sub { $_ = "fox comes and fox goes into forest"; s/(
+?<=fox)(.+?)(fox)/$1the $2/; });
print "Roy Jonhson\n";
timethis (999999, sub { $_ = "fox comes and fox goes into forest"; s/(
+?=fox(?:(?!.*fox).)*forest)/the /; });
[download]

prints:

holli
timethis 999999: 10 wallclock secs ( 9.87 usr +  0.00 sys =  9.87 CPU)
+ @ 101275.98/s (n=999999)
borisz
timethis 999999: 14 wallclock secs (11.08 usr +  0.00 sys = 11.08 CPU)
+ @ 90268.91/s (n=999999)
sh1tn
timethis 999999: 12 wallclock secs (10.41 usr +  0.01 sys = 10.42 CPU)
+ @ 95959.98/s (n=999999)
Roy Jonhson
timethis 999999: 10 wallclock secs (10.19 usr +  0.02 sys = 10.20 CPU)
+ @ 98000.69/s (n=999999)
[download]

/me wins ;-)

holli, /regexed monk/

Comment on Re^2: regexp find last word Select or Download Code

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Re^3: regexp find last word by Crackers2 (Parson) on Mar 02, 2005 at 15:45 UTC
That's all well for the speed, but let's check correctness: Testing string: fox comes and fox goes into forest `Holli : fox comes and the fox goes into forest Roy : fox comes and the fox goes into forest Borisz : fox comes and the fox goes into forest shltn : fox comes and the fox goes into forest` [download] Every solution got that one right. Testing string: fox comes fox walks and fox goes into forest `Holli : fox comes fox walks and the fox goes into forest Roy : fox comes fox walks and the fox goes into forest Borisz : fox comes fox walks and the fox goes into forest shltn : fox comes the fox walks and fox goes into forest` [download] Three foxes trip up shltn. Testing string: pig comes and fox goes into forest `Holli : pig comes and fox goes into forest Roy : pig comes and the fox goes into forest Borisz : pig comes and the fox goes into forest shltn : pig comes and fox goes into forest` [download] And just one fox trips up both Holli and shltn So I'm just going to pretend I have judging power and disqualify Holli's and shltn's entries, which makes Roy Jonhson the new winner. :)	[reply] [d/l] [select]
Re^4: regexp find last word by Anonymous Monk on Mar 03, 2005 at 10:46 UTC
Testing string: fox comes fox walks and fox goes into forest. no fox left `holli: fox comes fox walks and the fox goes into forest. no fox +left borisz: fox comes fox walks and the fox goes into forest. no fox +left sh1tn: fox comes the fox walks and fox goes into forest. no fox +left Roy Johnson: fox comes fox walks and fox goes into forest. no fox left` [download] And that trips both sh1tn and Roy Johnson. Leaving borisz as the only correct solution.	[reply] [d/l]
Re^3: regexp find last word by Roy Johnson (Monsignor) on Mar 02, 2005 at 16:00 UTC
With corrected versions of yours and mine, plus ikegami's suggested alteration of mine: `use strict; use warnings; use Benchmark 'cmpthese'; cmpthese( -2, { holli => sub { $_ = "fox comes and fox goes into forest"; s/(fox.+)?(fox.+?forest)/${1}the $2/; }, Roy => sub { $_ = "fox comes and fox goes into forest"; s/(?=fox(?:(?!fox).)forest)/the /; }, ikegami => sub { $_ = "fox comes and fox goes into forest"; s/(fox(?:(?!fox).)forest)/the $1/; }, });` [download] `Rate ikegami holli Roy ikegami 34714/s -- -2% -27% holli 35541/s 2% -- -25% Roy 47659/s 37% 34% --` [download] Caution: Contents may have been coded under pressure.	[reply] [d/l] [select]
Re^3: regexp find last word by ikegami (Patriarch) on Mar 02, 2005 at 15:45 UTC
You can remove the (redundant) .* from Roy Johnson's. I don't know if it helps any, but you can remove the lookahead too: `s/(fox(?:(?!fox).)*forest)/the $1/;`	[reply] [d/l]
Re^4: regexp find last word by Roy Johnson (Monsignor) on Mar 02, 2005 at 15:50 UTC
I removed the redundant .* about 2 minutes after I posted it. People see things quick around here. Caution: Contents may have been coded under pressure.	[reply]
Re^3: regexp find last word by valentin (Abbot) on Mar 02, 2005 at 21:12 UTC
Here is what I mensure on my PPC: use strict; use warnings; use Benchmark 'cmpthese'; cmpthese( -2, { holli => sub { $_ = "fox comes and fox goes into forest"; s/(fox.+)?(fox.+?forest)/${1}the $2/; }, Roy => sub { $_ = "fox comes and fox goes into forest"; s/(?=fox(?:(?!fox).)forest)/the /; }, ikegami => sub { $_ = "fox comes and fox goes into forest"; s/(fox(?:(?!fox).)forest)/the $1/; }, borisz => sub { $_ = reverse "fox comes and fox goes into forest"; s/(tserof.*?)xof/${1}xof eht/; $_ = reverse; } } ); __OUTPUT__ Rate holli ikegami Roy borisz holli 62934/s -- -3% -25% -31% ikegami 65121/s 3% -- -23% -29% Roy 84099/s 34% 29% -- -8% borisz 91530/s 45% 41% 9% -- [download]	[reply] [d/l]