R/clean_strings.R

In kamapu/taxlist: Handling Taxonomic Lists

#' @name clean_strings
#'
#' @title Cleaning character strings.
#'
#' @description
#' Multiple, leading and trailing white spaces as well as wrong encodings may
#' cause serious problems in information dealing with taxonomic names.
#' The function `clean_strings` get rid of them.
#'
#' @param x Object to be cleaned.
#' @param from,to Arguments passed to [iconv()].
#' @param ... Further arguments passed among methods (not yet in use).
#'
#' @details
#' This function automatically deletes leading, trailing and multiple white
#' spaces, either in strings (method `character`), levels (method
#' `factor` or in single columns (method `data.frame`).
#'
#' @return The same as input `x`.
#'
#' @author Miguel Alvarez.
#'
#' @example examples/clean_strings.R
#'
#' @rdname clean_strings
#'
#' @exportMethod clean_strings
setGeneric(
  "clean_strings",
  function(x, ...) {
    standardGeneric("clean_strings")
  }
)

#' @rdname clean_strings
#' @aliases clean_strings,character-method
setMethod(
  "clean_strings", signature(x = "character"),
  function(x, from = "utf8", to = "utf8", ...) {
    x <- iconv(x, from, to)
    x <- trimws(x, "both")
    x <- gsub("\\s+", " ", x)
    return(x)
  }
)

#' @rdname clean_strings
#' @aliases clean_strings,factor-method
setMethod(
  "clean_strings", signature(x = "factor"),
  function(x, from = "utf8", to = "utf8", ...) {
    base::levels(x) <- clean_strings(base::levels(x), from, to, ...)
    return(x)
  }
)

#' @rdname clean_strings
#' @aliases clean_strings,data.frame-method
setMethod(
  "clean_strings", signature(x = "data.frame"),
  function(x, from = "utf8", to = "utf8", ...) {
    for (i in colnames(x)) {
      if (is.character(x[, i]) | is.factor(x[, i])) {
        x[, i] <- clean_strings(x[, i], from, to)
      }
    }
    return(x)
  }
)