Removes list and enumeration markers — `"1."`, `"2."`, `"(i)"`, `"(a)"`, `"(iv)"`, `"IV."`, `"V."` — from each document. The `numbers`, `roman_numerals`, and `section_numbers` arguments of [topics()] clean only the extracted *terms*; this cleans the source *text*, so markers no longer over-fragment [segment()], skew the embeddings, or surface in [representatives()][representatives]. Run it once, before embedding or segmentation, as a companion to [dedupe()].
Value
`text` with markers removed and runs of whitespace collapsed to a single space; each element trimmed.
Details
A marker must stand alone — whitespace or a string boundary on both sides — so real words in parentheses (`"(civil)"`), four-digit years (`"(2020)"`), counts (`"(n=100)"`), multi-word parentheticals (`"(see Fig 1)"`), and decimals (`"1.5"`) are left untouched. Removed forms are a standalone one- or two-digit number followed by a period (`"1."`, `"12."`); a parenthesized one- or two-digit number, single letter, or Roman numeral up to 39 (`"(1)"`, `"(a)"`, `"(iv)"`); and a bare upper-case Roman-numeral section marker with a period (`"II."`, `"IV."`). A multi-letter numeral is removed anywhere; a single-letter one (`"V."`, `"X."`) only at the start of the text, so a mid-sentence initial (`"by V. Nabokov"`), unit (`"5 V."`), and lower-case `"v."` (versus) are kept.
See also
[dedupe()], and the `numbers` / `roman_numerals` / `section_numbers` arguments of [topics()] for cleaning the terms rather than the text.
Examples
strip_list_markers(c("1. background 2. methods", "(i) first (ii) second"))
#> [1] "background methods" "first second"
strip_list_markers("the concept of (civil) society in (2020)")
#> [1] "the concept of (civil) society in (2020)"