tokenizer: Tokenizers

Description Usage Arguments Details Value See Also Examples

Description

Tokenize a document or character vector.

Usage

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Arguments

x

A character vector, or an object that can be coerced to character by as.character.

Details

The quality and correctness of a tokenization algorithm highly depends on the context and application scenario. Relevant factors are the language of the underlying text and the notions of whitespace (which can vary with the used encoding and the language) and punctuation marks. Consequently, for superior results you probably need a custom tokenization function.

Boost_tokenizer

Uses the Boost (http://www.boost.org) Tokenizer (via Rcpp).

MC_tokenizer

Implements the functionality of the tokenizer in the MC toolkit (http://www.cs.utexas.edu/users/dml/software/mc/).

scan_tokenizer

Simulates scan(..., what = "character").

Value

A character vector consisting of tokens obtained by tokenization of x.

See Also

getTokenizers to list tokenizers provided by package tm.

Regexp_Tokenizer for tokenizers using regular expressions provided by package NLP.

tokenize for a simple regular expression based tokenizer provided by package tau.

tokenizers for a collection of tokenizers provided by package tokenizers.

Examples

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data("crude")
Boost_tokenizer(crude[[1]])
MC_tokenizer(crude[[1]])
scan_tokenizer(crude[[1]])
strsplit_space_tokenizer <- function(x)
    unlist(strsplit(as.character(x), "[[:space:]]+"))
strsplit_space_tokenizer(crude[[1]])

Example output

Loading required package: NLP
 [1] "Diamond"      "Shamrock"     "Corp"         "said"         "that"        
 [6] "effective"    "today"        "it"           "had"          "cut"         
[11] "its"          "contract"     "prices"       "for"          "crude"       
[16] "oil"          "by"           "1.50"         "dlrs"         "a"           
[21] "barrel."      "The"          "reduction"    "brings"       "its"         
[26] "posted"       "price"        "for"          "West"         "Texas"       
[31] "Intermediate" "to"           "16.00"        "dlrs"         "a"           
[36] "barrel,"      "the"          "copany"       "said."        "\"The"       
[41] "price"        "reduction"    "today"        "was"          "made"        
[46] "in"           "the"          "light"        "of"           "falling"     
[51] "oil"          "product"      "prices"       "and"          "a"           
[56] "weak"         "crude"        "oil"          "market,\""    "a"           
[61] "company"      "spokeswoman"  "said."        "Diamond"      "is"          
[66] "the"          "latest"       "in"           "a"            "line"        
[71] "of"           "U.S."         "oil"          "companies"    "that"        
[76] "have"         "cut"          "its"          "contract,"    "or"          
[81] "posted,"      "prices"       "over"         "the"          "last"        
[86] "two"          "days"         "citing"       "weak"         "oil"         
[91] "markets."     "Reuter"      
 [1] "Diamond"      "Shamrock"     "Corp"         "said"         "that"        
 [6] "effective"    "today"        "it"           "had"          "cut"         
[11] "its"          "contract"     "prices"       "for"          "crude"       
[16] "oil"          "by"           "dlrs"         "a"            "barrel"      
[21] "The"          "reduction"    "brings"       "its"          "posted"      
[26] "price"        "for"          "West"         "Texas"        "Intermediate"
[31] "to"           "dlrs"         "a"            "barrel"       "the"         
[36] "copany"       "said"         "The"          "price"        "reduction"   
[41] "today"        "was"          "made"         "in"           "the"         
[46] "light"        "of"           "falling"      "oil"          "product"     
[51] "prices"       "and"          "a"            "weak"         "crude"       
[56] "oil"          "market"       "a"            "company"      "spokeswoman" 
[61] "said"         "Diamond"      "is"           "the"          "latest"      
[66] "in"           "a"            "line"         "of"           "U"           
[71] "S"            "oil"          "companies"    "that"         "have"        
[76] "cut"          "its"          "contract"     "or"           "posted"      
[81] "prices"       "over"         "the"          "last"         "two"         
[86] "days"         "citing"       "weak"         "oil"          "markets"     
[91] "Reuter"      
 [1] "Diamond"      "Shamrock"     "Corp"         "said"         "that"        
 [6] "effective"    "today"        "it"           "had"          "cut"         
[11] "its"          "contract"     "prices"       "for"          "crude"       
[16] "oil"          "by"           "1.50"         "dlrs"         "a"           
[21] "barrel."      "The"          "reduction"    "brings"       "its"         
[26] "posted"       "price"        "for"          "West"         "Texas"       
[31] "Intermediate" "to"           "16.00"        "dlrs"         "a"           
[36] "barrel,"      "the"          "copany"       "said."        "\"The"       
[41] "price"        "reduction"    "today"        "was"          "made"        
[46] "in"           "the"          "light"        "of"           "falling"     
[51] "oil"          "product"      "prices"       "and"          "a"           
[56] "weak"         "crude"        "oil"          "market,\""    "a"           
[61] "company"      "spokeswoman"  "said."        "Diamond"      "is"          
[66] "the"          "latest"       "in"           "a"            "line"        
[71] "of"           "U.S."         "oil"          "companies"    "that"        
[76] "have"         "cut"          "its"          "contract,"    "or"          
[81] "posted,"      "prices"       "over"         "the"          "last"        
[86] "two"          "days"         "citing"       "weak"         "oil"         
[91] "markets."     "Reuter"      
 [1] "Diamond"      "Shamrock"     "Corp"         "said"         "that"        
 [6] "effective"    "today"        "it"           "had"          "cut"         
[11] "its"          "contract"     "prices"       "for"          "crude"       
[16] "oil"          "by"           "1.50"         "dlrs"         "a"           
[21] "barrel."      "The"          "reduction"    "brings"       "its"         
[26] "posted"       "price"        "for"          "West"         "Texas"       
[31] "Intermediate" "to"           "16.00"        "dlrs"         "a"           
[36] "barrel,"      "the"          "copany"       "said."        "\"The"       
[41] "price"        "reduction"    "today"        "was"          "made"        
[46] "in"           "the"          "light"        "of"           "falling"     
[51] "oil"          "product"      "prices"       "and"          "a"           
[56] "weak"         "crude"        "oil"          "market,\""    "a"           
[61] "company"      "spokeswoman"  "said."        "Diamond"      "is"          
[66] "the"          "latest"       "in"           "a"            "line"        
[71] "of"           "U.S."         "oil"          "companies"    "that"        
[76] "have"         "cut"          "its"          "contract,"    "or"          
[81] "posted,"      "prices"       "over"         "the"          "last"        
[86] "two"          "days"         "citing"       "weak"         "oil"         
[91] "markets."     "Reuter"      

tm documentation built on July 11, 2020, 3 a.m.