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ngrams not in correct order


ngrams not in correct order

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ngrams not in correct order
Tag : r , By : Moe Skeeto
Date : December 01 2020, 05:00 PM

I wish did fix the issue. I am interested to find the ngrams of a string x= "A T G C C G C G T" . I use the ngram R package to get the ngrams. I use following lines to get my job done. , Don't know about ngram but you should produce the output like this,
x= "A T G C C G C G T"
strsplit(gsub("(\\S)(?=\\s(\\S))|\\s+\\S$", "\\1\\2", x, perl=T), " ")[[1]]
# [1] "AT" "TG" "GC" "CC" "CG" "GC" "CG" "GT"

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Correct way to store uni/bi/trigrams ngrams in RDBMS?


Tag : mysql , By : Gerhard Miller
Date : March 29 2020, 07:55 AM
To fix the issue you can do This is how I would model your data (note that 'the' is referenced twice) You could also add weights to the single words.
DROP SCHEMA ngram CASCADE;
CREATE SCHEMA ngram;

SET search_path='ngram';

CREATE table word
    ( word_id INTEGER PRIMARY KEY 
    , the_word varchar
    , constraint word_the_word UNIQUE (the_word)
    );  
CREATE table ngram
    ( ngram_id INTEGER  PRIMARY KEY 
    , n INTEGER NOT NULL -- arity
    , weight REAL -- payload
    );  

CREATE TABLE ngram_word
    ( ngram_id INTEGER NOT NULL REFERENCES ngram(ngram_id)
    , seq INTEGER NOT NULL
    , word_id INTEGER NOT NULL REFERENCES word(word_id)
    , PRIMARY KEY (ngram_id,seq)
    );  

INSERT INTO word(word_id,the_word) VALUES
(1, 'the') ,(2, 'man') ,(3, 'who') ,(4, 'sold') ,(5, 'world' );

INSERT INTO ngram(ngram_id, n, weight) VALUES
(101, 6, 1.0);

INSERT INTO ngram_word(ngram_id,seq,word_id) VALUES
( 101, 1, 1)
, ( 101, 2, 2)
, ( 101, 3, 3)
, ( 101, 4, 4)
, ( 101, 5, 1)
, ( 101, 6, 5)
    ;   

SELECT w.*
FROM ngram_word nw
JOIN word w ON w.word_id = nw.word_id
WHERE ngram_id = 101
ORDER BY seq;
 word_id | the_word 
---------+----------
       1 | the
       2 | man
       3 | who
       4 | sold
       1 | the
       5 | world
(6 rows)
INSERT INTO word(word_id,the_word) VALUES
(6, 'is') ,(7, 'lost') ;

INSERT INTO ngram(ngram_id, n, weight) VALUES
(102, 4, 0.1);

INSERT INTO ngram_word(ngram_id,seq,word_id) VALUES
( 102, 1, 1)
, ( 102, 2, 2)
, ( 102, 3, 6)
, ( 102, 4, 7)
    ;   

SELECT w.*
FROM ngram_word nw
JOIN word w ON w.word_id = nw.word_id
WHERE ngram_id = 102
ORDER BY seq;
INSERT 0 2
INSERT 0 1
INSERT 0 4
 word_id | the_word 
---------+----------
       1 | the
       2 | man
       6 | is
       7 | lost
(4 rows)
 ngram_word.seq >0 AND ngram_word.seq <= (select ngram.n FROM ngram ng WHERE ng.ngram_id = ngram_word.ngram_id)

How to order the ngrams in Google's database (or the one hosted on AWS) by frequency


Tag : database , By : mtnmuncher
Date : March 29 2020, 07:55 AM
hop of those help? I would recommend using Pig!
Pig makes things like this very easy and straight-forward. Here's a sample pig script that does pretty much what you need:
raw = LOAD '/foo/input' USING PigStorage('\t') AS (ngram:chararray, year:int, count:int, pages:int, books:int);
filtered = FILTER raw BY year >= 1980;
grouped = GROUP filtered BY ngram;
counts = FOREACH grouped GENERATE group AS ngram, SUM(filtered.count) AS count;
sorted = ORDER counts BY count DESC;
limited = LIMIT sorted 10000;
STORED limited INTO '/foo/output' USING PigStorage('\t');

How to get the array of all ngrams in Perl Text::Ngrams


Tag : perl , By : Robby
Date : March 29 2020, 07:55 AM
will be helpful for those in need You can't get all the different sizes of n-grams at the same time, but you can get them all using multiple calls to get_ngrams. There is an undocumented parameter n to get_ngrams that says the size of the n-grams you want listed.
In your code, if you say
my @ngramsarray = $ng3->get_ngrams(
  n => 1,
  orderby = >'frequency',
  onlyfirst => 10,
  normalize => 0);
('T', 8, 'E', 4, 'X', 2, '_', 2, 'S', 2)

Is it possible to maintain order of ngrams in the output of textcnt function in R?


Tag : r , By : Blaise Roth
Date : March 29 2020, 07:55 AM
wish of those help I am using the textcnt() function from tau package to obtain bigrams as follows: , Try
library(tokenizers)
tokenize_ngrams(sentence, n = 2L)
# [[1]]
# [1] "a sample"        "sample sentence" "sentence in"     "in english"      "english for"     "for testing"     "testing purpose"

Finding ngrams in R and comparing ngrams across corpora


Tag : r , By : jaime
Date : March 29 2020, 07:55 AM
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