Split tokens by a separator pattern

Replaces tokens by multiple replacements consisting of elements split by a separator pattern, with the option of retaining the separator. This function effectively reverses the operation of tokens_compound().

tokens_split(
  x,
  separator = " ",
  valuetype = c("fixed", "regex"),
  remove_separator = TRUE,
  apply_if = NULL
)

Arguments

x

a tokens object

separator

a single-character pattern match by which tokens are separated

valuetype

the type of pattern matching: "glob" for "glob"-style wildcard expressions; "regex" for regular expressions; or "fixed" for exact matching. See valuetype for details.

remove_separator

if TRUE, remove separator from new tokens

apply_if

logical vector of length ndoc(x); documents are modified only when corresponding values are TRUE, others are left unchanged.

Examples

# undo tokens_compound()
toks1 <- tokens("pork barrel is an idiomatic multi-word expression")
tokens_compound(toks1, phrase("pork barrel"))
#> Tokens consisting of 1 document.
#> text1 :
#> [1] "pork_barrel" "is"          "an"          "idiomatic"   "multi-word" 
#> [6] "expression" 
#> 
tokens_compound(toks1, phrase("pork barrel")) |>
    tokens_split(separator = "_")
#> Tokens consisting of 1 document.
#> text1 :
#> [1] "pork"       "barrel"     "is"         "an"         "idiomatic" 
#> [6] "multi-word" "expression"
#> 

# similar to tokens(x, remove_hyphen = TRUE) but post-tokenization
toks2 <- tokens("UK-EU negotiation is not going anywhere as of 2018-12-24.")
tokens_split(toks2, separator = "-", remove_separator = FALSE)
#> Tokens consisting of 1 document.
#> text1 :
#>  [1] "UK"          "-"           "EU"          "negotiation" "is"         
#>  [6] "not"         "going"       "anywhere"    "as"          "of"         
#> [11] "2018"        "-"          
#> [ ... and 4 more ]
#>