R/charnum.R

In oliver-wyman-actuarial/easyR: Helpful Functions from Oliver Wyman Actuarial Consulting

#' Check for Number Formatted as Character.
#'
#' Checks a vector or value to see if it is a number formatted as a character. Useful for checking columns formatted with $ or commas, etc.
#' Author: Bryce Chamberlain. Tech review: Dominic Dillingham.
#'
#' @param x Vector to check.
#' @param na_strings Strings to consider NA.
#' @param run_unique Convert to unique variables before checking. In some cases, this can make it take longer than necessary. In most, it will make it faster.
#' @param check_date Check for a date, in which case it isn't a number. If you have already checked a date and know it isn't, set this to FALSE to run faster.
#' 
#' @return True/false value indicating if the vector is a number formatted as a character. Helpful for checking before calling easyr:tonum().
#' @export
#'
#' @examples
#' charnum( c( 
#'    '123', '$50.02', '30%', '(300.01)', '-10', '1 230.4', NA, '-', '', "3.7999999999999999E-2" 
#'  ))
#' charnum( c( '123', 'abc', '30%', NA) )
#' # returns FALSE since this can be converted to a date:
#' charnum( c( '20180101' ))
charnum <- function( x, na_strings = easyr::nastrings, run_unique = TRUE, check_date = TRUE ){

  if( !is.character(x) ) return(FALSE)
  
  test.convert = tonum( x, verbose = FALSE )
  
  return( is.numeric( test.convert ) )

}