Context is very important, varying analysis rankings and percentages are easily derived by drawing from different sample sizes, different authors; or different document types: poetry, science-fiction, technology documentation; and writing levels: stories for children versus adults, military orders, and recipes.
Because encrypted messages sent by telegraph often omit punctuation and spaces, cryptographic frequency analysis of such messages includes trigrams that straddle word boundaries. This causes trigrams such as "edt" to occur frequently, even though it may never occur in any one word of those messages.[4]
Examples
The sentence "the quick red fox jumps over the lazy brown dog" has the following word-level trigrams:
the quick red quick red fox red fox jumps fox jumps over jumps over the over the lazy the lazy brown lazy brown dog
And the word-level trigram "the quick red" has the following character-level trigrams (where an underscore "_" marks a space):
trigram, other, uses, disambiguation, this, article, needs, additional, citations, verification, please, help, improve, this, article, adding, citations, reliable, sources, unsourced, material, challenged, removed, find, sources, news, newspapers, books, schol. For other uses see Trigram disambiguation This article needs additional citations for verification Please help improve this article by adding citations to reliable sources Unsourced material may be challenged and removed Find sources Trigram news newspapers books scholar JSTOR December 2009 Learn how and when to remove this template message Trigrams are a special case of the n gram where n is 3 They are often used in natural language processing for performing statistical analysis of texts and in cryptography for control and use of ciphers and codes Frequency EditContext is very important varying analysis rankings and percentages are easily derived by drawing from different sample sizes different authors or different document types poetry science fiction technology documentation and writing levels stories for children versus adults military orders and recipes Typical cryptanalytic frequency analysis finds that the 16 most common character level trigrams in English are 1 2 Rank 1 Trigram Frequency 3 Different source 1 the 1 81 2 and 0 73 3 tha 0 33 4 ent 0 42 5 ing 0 72 6 ion 0 42 7 tio 0 31 8 for 0 34 9 nde10 has11 nce12 edt13 tis14 oft 0 22 15 sth 0 21 16 menBecause encrypted messages sent by telegraph often omit punctuation and spaces cryptographic frequency analysis of such messages includes trigrams that straddle word boundaries This causes trigrams such as edt to occur frequently even though it may never occur in any one word of those messages 4 Examples EditThe sentence the quick red fox jumps over the lazy brown dog has the following word level trigrams the quick red quick red fox red fox jumps fox jumps over jumps over the over the lazy the lazy brown lazy brown dog And the word level trigram the quick red has the following character level trigrams where an underscore marks a space the he e q qu qui uic ick ck k r re redReferences Edit a b Lewand Robert 2000 Cryptological Mathematics The Mathematical Association of America p 37 ISBN 978 0 88385 719 9 Linton Tom 2001 Relative Frequencies of Letters in General English Plain text Central College Cryptography Spring ed Archived from the original on January 22 2007 English Letter Frequencies Practical Cryptography Voice Search SEO Fuelonline Retrieved from https en wikipedia org w index php title Trigram amp oldid 1048493768, wikipedia, wiki, book, books, library,
