R/rx.R

In EmilHvitfeldt/emoji: Data and Function to Work with Emojis

#' A regular expression to catch all emojis
#'
#' This regex will capture all `fully-qualified` and `minimally-qualified`
#' emojis.
#'
#' @source \url{https://www.unicode.org/reports/tr51/#emoji_data}
#'
#' @format character vector
"emoji_rx"

#' Detect the presence or absence of emojis in a string
#'
#' Vectorised over `string`
#'
#' @param string Input vector. Either a character vector, or something coercible
#'     to one.
#' @inheritParams stringr::str_detect
#'
#' @return A logical vector
#' @seealso [stringr::str_detect()]
#'
#' @examples
#' string <- c(letters[1:4], emoji_name[1:6])
#' emoji_detect(string)
#'
#' @export
emoji_detect <- function(string, negate = FALSE) {
  str_detect(string, emoji::emoji_rx, negate)
}

#' Keep strings containing an emoji, or find positions
#'
#' @param string input vector
#' @inheritParams stringr::str_subset
#'
#' @return A character vector
#'
#' @seealso [stringr::str_subset()]
#'
#' @examples
#' string <- c(letters[1:4], emoji_name[1:6])
#'
#' emoji_subset(string) == emoji_name[1:6]
#' emoji_subset(string, negate = TRUE)
#' @export
emoji_subset <- function(string, negate = FALSE) {
  str_subset(string, emoji::emoji_rx, negate)
}

#' @rdname emoji_subset
#'
#' @examples
#'
#' emoji_which(string)
#' emoji_which(string, negate = TRUE)
#' @export
emoji_which <- function(string, negate = FALSE) {
  str_which(string, emoji::emoji_rx, negate)
}

#' Count the number of emojis in a string
#'
#' Vectorised over `string`
#'
#' @param string Input vector
#' @return An integer vector
#' @seealso [stringr::str_count()]
#' @examples
#' string <- paste(c(letters[1:4], emoji_name[1:6]), collapse = " ")
#'
#' emoji_count(string)
#'
#' emoji_count(emoji_name[1:6])
#' @export
emoji_count <- function(string) str_count(string, emoji::emoji_rx)

#' Extract emojis from a string
#'
#' vectorised over `string`
#'
#' @param string Input vector.
#' @param simplify see [stringr::str_extract_all()]
#'
#' @seealso [stringr::str_extract()] and [stringr::str_extract_all()]
#' @return A character vector
#'
#' @examples
#' chars <- c(letters[1:4], emoji_name[1:6])
#'
#' set.seed(1234)
#'
#' strings <- lapply(1:10, function(x) paste(sample(chars, x), collapse = ""))
#'
#' extracts <- emoji_extract(strings)
#' @export
emoji_extract <- function(string) str_extract(string, emoji::emoji_rx)

#' @rdname emoji_extract
#'
#' @examples
#'
#' all_extracts <- emoji_extract_all(strings)
#' @export
emoji_extract_all <- function(string, simplify = FALSE) {
  str_extract_all(string, emoji::emoji_rx, simplify)
}

#' Extract matched emojis from a string
#'
#' Vectorized over `string`
#'
#' @param string Input vector
#' @return see [stringr::str_match()]
#'
#' @seealso [stringr::str_match]
#'
#' @examples
#' chars <- c(letters[1:4], emoji_name[1:6])
#'
#' set.seed(1234)
#'
#' strings <- lapply(1:10, function(x) paste(sample(chars, x), collapse = ""))
#'
#' extracts <- emoji_match(strings)
#'
#' @export
emoji_match <- function(string) str_match(string, emoji::emoji_rx)

#' @rdname emoji_match
#'
#' @examples
#'
#' extracts <- emoji_match_all(strings)
#' @export
emoji_match_all <- function(string) str_match_all(string, emoji::emoji_rx)

#' Replace emojis in a string
#'
#' Vectorised over `string` and `replacement`
#'
#' @param string Input vector
#' @param replacement A character vector of replacements. Should either be
#'   of length 1 or the same length as `string`. See [stringr::str_replace()]
#'   for details
#'
#' @return A character vector
#'
#' @examples
#' emoji_replace(emoji_name[1], "_emoji_")
#' @export
emoji_replace <- function(string, replacement) {
  str_replace(string, emoji::emoji_rx, replacement)
}

#' @rdname emoji_replace
#'
#' @examples
#'
#' string <- paste(c(letters[1:4], emoji_name[1:6]), collapse = " ")
#'
#' emoji_replace_all(emoji_name[1:6], "_emoji_")
#' @export
emoji_replace_all <- function(string, replacement) {
  str_replace_all(string, emoji::emoji_rx, replacement)
}

#' Replace emojis in a string with name
#'
#' Vectorised over `string`
#'
#' Each emoji is replaced with human readable string in the form 
#' `:name_of_emoji:`.
#' 
#' @param string Input vector
#'
#' @return A character vector
#'
#' @examples
#' example <- c(
#'   paste0("This is an emoji; ", emoji("person_facepalming")),
#'   paste0("You can write slides in ", emoji("key"), emoji("musical_note"))
#' )
#' 
#' example
#' 
#' emoji_replace_name(example)
#' @export
emoji_replace_name <- function(string) {
  emoji_dict <- stats::setNames(
    paste0(":", names(emoji::emoji_name), ":"),
    unname(emoji::emoji_name)
  )

  # these two emojis mess things up
  emoji_dict <- emoji_dict[!emoji_dict %in% c(":asterisk:", ":keycap_star:")]
  
  # make sure emojis with qualifiers gets replaces first
  emoji_dict <- rev(sort(emoji_dict))
  
  stringr::str_replace_all(string, emoji_dict)
}

#' Locate the position of emojis in a string
#'
#' Vectorised over `string`
#'
#' @param string Input vector
#' @return For `emoji_locate` an integer matrix, for `emoji_locate_all` a list
#'   of integer matrices
#'
#' @examples
#' string <- paste(c(letters[1:4], emoji_name[1:6]), collapse = " ")
#'
#' emoji_locate(string)
#' @export
emoji_locate <- function(string) str_locate(string, emoji::emoji_rx)

#' @rdname emoji_locate
#'
#' @examples
#'
#' emoji_locate_all(string)
#' @export
emoji_locate_all <- function(string) str_locate_all(string, emoji::emoji_rx)