stringi-search-boundaries {stringi} | R Documentation

## Text Boundary Analysis in stringi

### Description

Text boundary analysis is the process of locating linguistic boundaries while formatting and handling text.

### Details

Examples of the boundary analysis process process include:

- Locating appropriate points to word-wrap text to fit within specific margins while displaying or printing, see `stri_wrap` and `stri_split_boundaries`.

- Counting characters, words, sentences, or paragraphs, see `stri_count_boundaries`.

- Making a list of the unique words in a document, cf. `stri_extract_all_words` and then `stri_unique`.

- Capitalizing the first letter of each word or sentence, see also `stri_trans_totitle`.

- Locating a particular unit of the text (for example, finding the third word in the document), see `stri_locate_all_boundaries`.

Generally, text boundary analysis is a locale-dependent operation. For example, in Japanese and Chinese one does not separate words with spaces - a line break can occur even in the middle of a word. These languages have punctuation and diacritical marks that cannot start or end a line, so this must also be taken into account.

stringi uses ICU's `BreakIterator` to locate specific text boundaries. Note that the `BreakIterator`'s behavior may be controlled in come cases, see `stri_opts_brkiter`.

- The `character` boundary iterator tries to match what a user would think of as a “character” – a basic unit of a writing system for a language – which may be more than just a single Unicode code point.

- The `word` boundary iterator locates the boundaries of words, for purposes such as “Find whole words” operations.

- The `line_break` iterator locates positions that would be appropriate points to wrap lines when displaying the text.

- On the other hand, a break iterator of type `sentence` locates sentence boundaries.

For technical details on different classes of text boundaries refer to the ICU User Guide, see below.

### References

Boundary Analysis – ICU User Guide, http://userguide.icu-project.org/boundaryanalysis

### See Also

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

Other stringi_general_topics: `stringi-arguments`, `stringi-encoding`, `stringi-locale`, `stringi-package`, `stringi-search-charclass`, `stringi-search-coll`, `stringi-search-fixed`, `stringi-search-regex`, `stringi-search`

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

[Package stringi version 1.1.1 Index]