concatHtmlTables(tables, headers = NULL)

library(magrittr)

# Basic example
output <- matrix(1:4,
                 ncol=2,
                 dimnames = list(list("Row 1", "Row 2"),
                                 list("Column 1", "Column 2")))
htmlTable(output)

############################################
# Below saves all outputs to a list that   #
# it outputted all at once at the end      #
# this is mostly for allowing you to view  #
# and evaluate each example section as     #
# they would otherwise be overwritten by   #
# eachother                                #
############################################
all_tables <- list()
htmlTable(output) ->
  all_tables[["Basic table"]]

# An advanced output
output <-
  matrix(ncol=6, nrow=8)

for (nr in 1:nrow(output)){
  for (nc in 1:ncol(output)){
    output[nr, nc] <-
      paste0(nr, ":", nc)
  }
}

output %>%
  addHtmlTableStyle(align="r",
                    col.columns = c(rep("none", 2),
                                    rep("#F5FBFF", 4)),
                    col.rgroup = c("none", "#F7F7F7"),
                    css.cell = "padding-left: .5em; padding-right: .2em;") %>%
  htmlTable(header =  paste(c("1st", "2nd",
                              "3rd", "4th",
                              "5th", "6th"),
                            "hdr"),
            rnames = paste(c("1st", "2nd",
                             "3rd",
                             paste0(4:8, "th")),
                           "row"),
            rgroup = paste("Group", LETTERS[1:3]),
            n.rgroup = c(2,4,nrow(output) - 6),
            cgroup = rbind(c("", "Column spanners", NA),
                           c("", "Cgroup 1", "Cgroup 2&dagger;")),
            n.cgroup = rbind(c(1,2,NA),
                             c(2,2,2)),
            caption="Basic table with both column spanners (groups) and row groups",
            tfoot="&dagger; A table footer commment",
            cspan.rgroup = 2) ->
  all_tables[["Advanced table"]]

# An advanced empty table
suppressWarnings({
  matrix(ncol = 6,
         nrow = 0) %>%
    addHtmlTableStyle(col.columns = c(rep("none", 2),
                                      rep("#F5FBFF", 4)),
                      col.rgroup = c("none", "#F7F7F7"),
                      css.cell = "padding-left: .5em; padding-right: .2em;") %>%
    htmlTable(align="r",
              header =  paste(c("1st", "2nd",
                                "3rd", "4th",
                                "5th", "6th"),
                              "hdr"),
              cgroup = rbind(c("", "Column spanners", NA),
                             c("", "Cgroup 1", "Cgroup 2&dagger;")),
              n.cgroup = rbind(c(1,2,NA),
                               c(2,2,2)),
              caption="Basic empty table with column spanners (groups) and ignored row colors",
              tfoot="&dagger; A table footer commment",
              cspan.rgroup = 2) ->
    all_tables[["Empty table"]]
})

# An example of how to use the css.cell for header styling
simple_output <- matrix(1:4, ncol=2)

simple_output %>%
  addHtmlTableStyle(css.cell = rbind(rep("background: lightgrey; font-size: 2em;",
                                         times=ncol(simple_output)),
                                     matrix("",
                                            ncol=ncol(simple_output),
                                            nrow=nrow(simple_output)))) %>%
  htmlTable(header = LETTERS[1:2]) ->
  all_tables[["Header formatting"]]

concatHtmlTables(all_tables)
# See vignette("tables", package = "htmlTable")
# for more examples