R: Extract Text Between Text Boundaries

stri_extract_all_boundaries {stringi} | R Documentation

## Extract Text Between Text Boundaries

### Description

These functions extract text between specific text boundaries.

### Usage

    stri_extract_all_boundaries(str, simplify = FALSE, omit_no_match = FALSE,
      ..., opts_brkiter = NULL)

    stri_extract_last_boundaries(str, ..., opts_brkiter = NULL)

    stri_extract_first_boundaries(str, ..., opts_brkiter = NULL)

    stri_extract_all_words(str, simplify = FALSE, omit_no_match = FALSE,
      locale = NULL)

    stri_extract_first_words(str, locale = NULL)

    stri_extract_last_words(str, locale = NULL)

### Arguments

`str` | character vector or an object coercible to
`simplify` | single logical value; if `TRUE` or `NA`, then a character matrix is returned; otherwise (the default), a list of character vectors is given, see Value
`omit_no_match` | single logical value; if `FALSE`, then a missing value will indicate that there are no words
`...` | additional settings for `opts_brkiter`
`opts_brkiter` | a named list with ICU BreakIterator's settings as generated with `stri_opts_brkiter`; `NULL` for default break iterator, i.e. `line_break`
`locale` | `NULL` or `""` for text boundary analysis following the conventions of the default locale, or a single string with locale identifier, see stringi-locale.

### Details

Vectorized over `str`.

For more information on the text boundary analysis performed by ICU's `BreakIterator`, see stringi-search-boundaries.

In case of `stri_extract_*_words`, Just like in `stri_count_words`, ICU's word `BreakIterator` iterator is used to locate word boundaries, and all non-word characters (`UBRK_WORD_NONE` rule status) are ignored.

### Value

For `stri_extract_all_*`, if `simplify=FALSE` (the default), then a list of character vectors is returned. Each string consists of a separate word. In case of `omit_no_match=FALSE` and if there are no words or if a string is missing, a single `NA` is provided on output. Otherwise, `stri_list2matrix` with `byrow=TRUE` argument is called on the resulting object. In such a case, a character matrix with `length(str)` rows is returned. Note that `stri_list2matrix`'s `fill` argument is set to an empty string and `NA`, for `simplify` equal to `TRUE` and `NA`, respectively.

For `stri_extract_first_*` and `stri_extract_last_*`, a character vector is returned. A `NA` element indicates no match.

### See Also

Other search_extract: `stri_extract_all`, `stri_match_all`, `stringi-search`

Other locale_sensitive: `%s<%`, `stri_compare`, `stri_count_boundaries`, `stri_duplicated`, `stri_enc_detect2`, `stri_locate_all_boundaries`, `stri_opts_collator`, `stri_order`, `stri_split_boundaries`, `stri_trans_tolower`, `stri_unique`, `stri_wrap`, `stringi-locale`, `stringi-search-boundaries`, `stringi-search-coll`

Other text_boundaries: `stri_count_boundaries`, `stri_locate_all_boundaries`, `stri_opts_brkiter`, `stri_split_boundaries`, `stri_split_lines`, `stri_trans_tolower`, `stri_wrap`, `stringi-search-boundaries`, `stringi-search`

### Examples

    stri_extract_all_words("stringi: THE string processing package 123.48...")

[Package stringi version 1.2.4 Index]