Sort data frame by letter column. Handles multiple letter cases A, B, ..., AA, ..., AAA,.... as commonly found in Excel spreadsheets.

SortByLetterColumn.R

SortByLetterColumn <- function(df, column_to_sort_by) {
  # Sorts a data frame by a column containing letters. E.g., A, B, C, ..., AA, BB,...
  #
  # Args:
  #   df: data frame to be sorted
  #   column_to_sort_by: (str) column to sort df by
  #
  # Returns:
  #   Data frame sorted by specified column.
  sorted <- df[order(nchar(df[,column_to_sort_by]), df[,column_to_sort_by]), ]  
  return(sorted)
}