in reply to Re^2: Character encoding woes - unicode or not?
in thread Character encoding woes - unicode or not?
Encode::Detect is my new best friend, thanks to Anonymous Monk.Then you don't know it very well. It’s really rather poor. Here are the failure results on a small sampling of real-world test files:
I have a working snapshot of a module that actually does work right on such things called Encode::Guess::Educated. It has no noncore dependencies. It is designed to detect the encoding of English-language biomedical research papers. It can reliably detect not merely ASCII and UTF-{8,16,32}, but also the very conflicting 8-bit encodings.Status Filename Right E::D::Detector ================================================== Wrong! 7843118 ascii UNABLE TO GUESS 9501430 utf8 UTF-8 10318897 cp1252 windows-1252 10329150 cp1252 windows-1252 Wrong! 10358003 MacRoman UNABLE TO GUESS Wrong! 10358042 MacRoman UNABLE TO GUESS Wrong! 10429209 MacRoman UNABLE TO GUESS 10482611 cp1252 windows-1252 Wrong! 10542098 MacRoman UNABLE TO GUESS 10617571 cp1252 windows-1252 Wrong! 10625668 iso-8859-1 windows-1252 10676968 cp1252 windows-1252 10677497 cp1252 windows-1252 10963661 MacRoman UNABLE TO GUESS 11042188 macRoman UNABLE TO GUESS 11212329 utf8 UTF-8 11287402 cp1252 windows-1252 Wrong! 11470876 MacRoman windows-1252 11842027 iso-8859-1 windows-1252 Wrong! 11940257 ascii UNABLE TO GUESS Wrong! 11972335 MacRoman UNABLE TO GUESS Wrong! 12091502 iso-8859-1 windows-1252 12169614 utf8 UTF-8 12495435 MacRoman windows-1252 12736309 MacRoman windows-1252 14641909 MacRoman windows-1252 14652344 utf8 UTF-8 14751857 cp1252 windows-1252 15037632 cp1252 windows-1252 15070898 cp1252 windows-1252 Wrong! 15154606 MacRoman windows-1252 15201223 cp1252 windows-1252 Wrong! 15315962 iso-8859-1 Big5 15328020 cp1252 windows-1252 Wrong! 17298172 MacRoman windows-1252 Wrong! 116059400 MacRoman windows-1252
The reason it can do this is that it works off a training model. I looked at three different corpora to do this: one containing 3½M non-ASCII codepoints, one containing 14M of them, and one containing 29M of them. It makes an educated guest based on conformance to a particular model. And it does very well.
Right now it has only a CLI API and an OO API, no Export-based one. Here’s the easiest way to use the CLI API, via a simple program called gank:
The underlying class’s default training model derives from the complete PubMed Open Access corpus, and it therefore attains an extremely high measured accuracy of 99.79% when used on English-language biomedical texts. It also does well on other texts using any Latin-based alphabet. I have comparative statistics using two alternate training models, but the PMCOA model is fine for most purposes.$ gank 011526914.txt cp1252 $ gank 00*.txt Sym*.txt 0115*.txt 001313968.txt: ascii 001328180.txt: utf8 007499277.txt: iso-8859-1 Symbola602.txt: UTF-16 011526914.txt: cp1252 011535589.txt: iso-8859-1 011570876.txt: MacRoman
You may also give gank a -s option to give you a short ‘score-card’ of the various encodings it considered:
EXPLANATION:*91.718532 +2.285393 MacRoman 3.640513 -0.941206 iso-8859-1, iso-8859-15, cp1252 3.639257 -0.941552 cp1250 1.001698 -2.231634 iso-8859-2
- The first column is all scores normalized to 0..100.
- The second column is the natural log of the real score.
- The rest is which encoding have that score, and in the order of preference for breaking ties of the same score. I have it arranged so it says it’s the smallest subset that works; i.e., ascii < latin1 < cp1252, etc.
total bytes=15903, high bytes=22, distinct high bytes=8 *49.582509 +0.909655 cp1252 => "I–V, Copyright © 2001 Outline • Acknowledgements 12000× g Südhof Marquèze, Llinás. ScienceDirect® is" => "I\N{EN DASH}V, Copyright \N{COPYRIGHT SIGN} 2001 Outline \N{BULLET} Acknowledgements 12000\N{MULTIPLICATION SIGN} g S\N{LATIN SMALL LETTER U WITH DIAERESIS}dhof Marqu\N{LATIN SMALL LETTER E WITH GRAVE}ze, Llin\N{LATIN SMALL LETTER A WITH ACUTE}s. ScienceDirect\N{REGISTERED SIGN} is" 49.557280 +0.909146 cp1250 => "I–V, Copyright © 2001 Outline • Acknowledgements 12000× g Südhof Marqučze, Llinás. ScienceDirect® is" => "I\N{EN DASH}V, Copyright \N{COPYRIGHT SIGN} 2001 Outline \N{BULLET} Acknowledgements 12000\N{MULTIPLICATION SIGN} g S\N{LATIN SMALL LETTER U WITH DIAERESIS}dhof Marqu\N{LATIN SMALL LETTER C WITH CARON}ze, Llin\N{LATIN SMALL LETTER A WITH ACUTE}s. ScienceDirect\N{REGISTERED SIGN} is" 0.860211 -3.144560 MacRoman => "IñV, Copyright © 2001 Outline ï Acknowledgements 12000◊ g S¸dhof MarquËze, Llin·s. ScienceDirectÆ is" => "I\N{LATIN SMALL LETTER N WITH TILDE}V, Copyright \N{COPYRIGHT SIGN} 2001 Outline \N{LATIN SMALL LETTER I WITH DIAERESIS} Acknowledgements 12000\N{LOZENGE} g S\N{CEDILLA}dhof Marqu\N{LATIN CAPITAL LETTER E WITH DIAERESIS}ze, Llin\N{MIDDLE DOT}s. ScienceDirect\N{LATIN CAPITAL LETTER AE} is"I need to do more work on its API — this is just a proof of concept, although it does comes with a halfway decent test suite — and of course document it, but I’m hunkered down right now correcting page-proofs on Camel4, so I probably won’t get to sprucing up the module for another 7–10 days.
--tom
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