Write data tables to Excel (.xlsx) file

wxls <- function(x, file = "test", ...)
{ 
    ## Purpose: Write data tables to Excel (.xlsx) file.
    ##          Require package "openxlsx". 
    ## Arguments:
    ##   x: a data frame or a list of data frames. 
    ##   file: a naked file name with no extension.
    ##   ...: passed to "write.xlsx". 
    ## Return: Generate an Excel (.xlsx) file.
    ## Author: Feiming Chen, Date:  6 Jun 2017, 15:11
    ## ________________________________________________
    
    require(openxlsx)
    f <- paste0(file, ".xlsx")

    write.xlsx(x, file = f, asTable = TRUE,
               creator = "Feiming Chen", 
               tableStyle = "TableStyleMedium2",   ...)
}
if (F) {                                # Unit Test
    df <- data.frame("Date" = Sys.Date()-0:4,
                     "Logical" = c(TRUE, FALSE, TRUE, TRUE, FALSE),
                     "Currency" = paste("$",-2:2),
                     "Accounting" = -2:2,
                     "hLink" = "https://CRAN.R-project.org/",
                     "Percentage" = seq(-1, 1, length.out=5),
                     "TinyNumber" = runif(5) / 1E9, stringsAsFactors = FALSE)
    class(df$Currency) <- "currency"
    class(df$Accounting) <- "accounting"
    class(df$hLink) <- "hyperlink"
    class(df$Percentage) <- "percentage"
    class(df$TinyNumber) <- "scientific"

    wxls(df)

    wxls(list(A = df, B = df, C= df))   # write to 3 separate tabs with corresponding list names. 
}