R: Locate Text Boundaries

stri_locate_all_boundaries {stringi} | R Documentation

## Locate Text Boundaries

### Description

These functions locate text boundaries (like character, word, line, or sentence boundaries). Use `stri_locate_all_*` to locate all the matches. `stri_locate_first_*` and `stri_locate_last_*` give the first or the last matches, respectively.

### Usage

    stri_locate_all_boundaries(
      str,
      omit_no_match = FALSE,
      ...,
      opts_brkiter = NULL
    )

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

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

    stri_locate_all_words(str, omit_no_match = FALSE, locale = NULL)

    stri_locate_last_words(str, locale = NULL)

    stri_locate_first_words(str, locale = NULL)

### Arguments

`str` | character vector or an object coercible to
`omit_no_match` | single logical value; if `FALSE`, then 2 missing values will indicate that there are no text boundaries
`...` | additional settings for `opts_brkiter`
`opts_brkiter` | a named list with ICU BreakIterator's settings, see `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 text boundary analysis performed by ICU's `BreakIterator`, see stringi-search-boundaries.

In case of `stri_locate_*_words`, just like in `stri_extract_all_words` and `stri_count_words`, ICU's word `BreakIterator` iterator is used to locate the word boundaries, and all non-word characters (`UBRK_WORD_NONE` rule status) are ignored. This is function is equivalent to a call to `stri_locate_*_boundaries(str, type="word", skip_word_none=TRUE, locale=locale)`

### Value

For `stri_locate_all_*`, a list of `length(str)` integer matrices is returned. The first column gives the start positions of substrings between located boundaries, and the second column gives the end positions. The indexes are code point-based, thus they may be passed, e.g., to `stri_sub` or `stri_sub_all`. Note that you get two `NA`s in one row if there is no match (and `omit_no_match` is `FALSE`) or there are missing data in the input vector.

`stri_locate_first_*` and `stri_locate_last_*`, return an integer matrix with two columns, giving the start and end positions of the first or the last matches, respectively, and two `NA`s if there is no match.

### See Also

Other search_locate: `stri_locate_all()`, `stringi-search`

Other indexing: `stri_locate_all()`, `stri_sub_all()`, `stri_sub()`

Other locale_sensitive: `%s<%()`, `stri_compare()`, `stri_count_boundaries()`, `stri_duplicated()`, `stri_enc_detect2()`, `stri_extract_all_boundaries()`, `stri_opts_collator()`, `stri_order()`, `stri_sort()`, `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_extract_all_boundaries()`, `stri_opts_brkiter()`, `stri_split_boundaries()`, `stri_split_lines()`, `stri_trans_tolower()`, `stri_wrap()`, `stringi-search-boundaries`, `stringi-search`

### Examples

    test <- "The\u00a0above-mentioned    features are very useful. Kudos to their developers."
    stri_locate_all_boundaries(test, type="line")
    stri_locate_all_boundaries(test, type="word")
    stri_locate_all_boundaries(test, type="sentence")
    stri_locate_all_boundaries(test, type="character")
    stri_locate_all_words(test)

    stri_extract_all_boundaries("Mr. Jones and Mrs. Brown are very happy.
    So am I, Prof. Smith.", type="sentence", locale="en_US@ss=standard") # ICU >= 56 only

[Package stringi version 1.4.6 Index]