Add footnote
@description Add footnote to your favorite kable output.
@param input The direct output of your function or your last function. @param label A vector of footnotes you want to add. You don’t need to add notations in your notes. @param notation You can select the format of your footnote notation from number, alphabet and symbol. @param threeparttable Boolean value indicating if a scheme should be used. @param escape Logical value controlling if the label needs to be escaped. Default is TRUE.
@examples x <- knitr::kable(head(mtcars), “html”) add_footnote(x, c(“footnote 1”, “footnote 2”), notation = “symbol”)
@export
add_footnote <- function(input, label = NULL,
notation = "alphabet",
threeparttable = FALSE,
escape = TRUE) {
if (is.null(label)) return(input)
if (notation == "alphabet") {
notation <- getOption("kable_footnote_notation", "alphabet")
}
if (!threeparttable) {
threeparttable <- getOption("kable_footnote_threeparttable", FALSE)
}
notation <- match.arg(notation, c("alphabet", "number", "symbol"))
if (notation == "symbol") {
notation <- paste0(notation, ".", attr(input, "format"))
}
table_info <- NULL
ids.ops <- read.csv(system.file("symbol_index.csv", package = "kableExtra"))
ids <- ids.ops[, notation]
ids.intable <- gsub("\\*", "\\\\*", ids)
#count the number of items in label and intable notation
count.label <- length(label)
count.intablenote <- sum(str_count(input, "\\[note\\]"))
if (count.intablenote != 0 & count.label != count.intablenote) {
warning(paste("You entered", count.label, "labels but you put",
count.intablenote, "[note] in your table."))
}
export <- input
# Find out if there are any extra in-table notations needed to be corrected
extra.notation <- unique(as.numeric(
str_extract(
str_extract_all(
paste0(export, collapse = ""), "\\[note[0-9]{1,2}\\]"
)[[1]],
"[0-9]{1,2}")))
# Pandoc ---------------------------
# Footnote solution for markdown and pandoc. It is not perfect as
# markdown doesn't support complex table formats but this solution
# should be able to satisfy people who don't want to spend extra
# time to define their `kable` format.
if (!attr(input, "format") %in% c("html", "latex")) {
# In table notation
if (count.intablenote != 0) {
for (i in 1:count.intablenote) {
replace_note <- paste0("^", ids.intable[i], "^",
paste0(rep(" ", 4 - ceiling(i/5)), collapse = ""))
export[which(str_detect(export, "\\[note\\]"))[1]] <-
sub("\\[note\\]", replace_note,
export[which(str_detect(export, "\\[note\\]"))[1]])
}
}
# Fix extra in table notation
for (i in extra.notation) {
export <- gsub(paste0("\\[note", i, "\\]"),
paste0("^", ids.intable[i], "^",
paste0(rep(" ", 4 - ceiling(i/5)), collapse = "")),
export)
}
export[length(export) + 1] <- ""
export[length(export) + 1] <- "__Note:__"
export[length(export) + 1] <- paste0(
paste0("^", ids[1:length(label)], "^ ", label), collapse = " "
)
}
# LaTeX Tables --------------------------------
if (attr(input, "format") == "latex") {
# Clean the entry for labels
if (escape) {
label <- escape_latex(label)
}
label <- gsub("\\\\", "\\\\\\\\", label)
export <- enc2utf8(export)
table_info <- magic_mirror(input)
if (table_info$tabular == "longtable") {
if (notation != "number") {
warning("Notation is set to 'number' and other formats are not supported.")
notation <- "number"
}
# If longtable is used, then use page footnote instead of threeparttable
# as it makes more sense to see the footnote at the bottom of page if
# table is longer than one page.
if (threeparttable == T) {
warning("Threeparttable does not support longtable.")
threeparttable = F
}
# Longtable doesn't support footnote in caption directly.
# See http://tex.stackexchange.com/questions/50151/footnotes-in-longtable-captions
count.in.caption.note <- 0
if (!is.na(table_info$caption)) {
count.in.caption.note <- str_count(table_info$caption, "\\[note\\]")
}
if (count.in.caption.note != 0) {
caption.footnote <- paste0("\\\\addtocounter{footnote}{-",
count.in.caption.note, "}")
for (i in 1:count.in.caption.note) {
export <- sub("\\[note\\]", "\\\\protect\\\\footnotemark ", export)
caption.footnote <- paste0(
caption.footnote, "\n\\\\stepcounter{footnote}\\\\footnotetext{",
label[i], "}")
}
if (str_detect(export, "\\\\toprule")) {
export <- sub("\\\\toprule",
paste0("\\\\toprule\n", caption.footnote), export)
} else {
export <- sub("\\\\hline",
paste0("\\\\hline\n", caption.footnote), export)
}
}
for (i in (count.in.caption.note + 1):count.intablenote) {
export <- sub("\\[note\\]",
paste0("\\\\footnote[", i, "]{", label[i], "}"), export)
}
for (i in extra.notation) {
export <- gsub(paste0("\\[note", i, "\\]"),
paste0("\\\\footnotemark[", i, "]"),
export)
}
} else {
# Replace in-table notation with appropriate symbol
for (i in 1:count.intablenote) {
export <- sub("\\[note\\]",
paste0("\\\\textsuperscript{", ids.intable[i], "}"),
export)
}
# Fix extra in table notation
for (i in extra.notation) {
export <- gsub(paste0("\\[note", i, "\\]"),
paste0("\\\\textsuperscript{", ids.intable[i], "}"),
export)
}
if (threeparttable == T) {
# generate footer with appropriate symbol
usepackage_latex("threeparttable")
footer <- ""
for (i in 1:count.label) {
footer <- paste0(footer,"\\\\item [", ids[i], "] ", label[i], "\n")
}
if (grepl("\\\\caption\\{.*?\\}", export)) {
export <- sub("\\\\caption\\{",
"\\\\begin{threeparttable}\n\\\\caption{",
export)
} else {
export <- sub(paste0("\\\\begin\\{", table_info$tabular, "\\}"),
paste0("\\\\begin{threeparttable}\n\\\\begin{",
table_info$tabular, "}"),
export)
}
export <- gsub(
"\\\\end\\{tabular\\}",
paste0("\\\\end{tabular}\n\\\\begin{tablenotes}\n\\\\small\n",
footer, "\\\\end{tablenotes}\n\\\\end{threeparttable}"),
export)
} else {
table.width <- max(nchar(
str_replace_all(
str_replace_all(table_info$contents, "\\[note\\]", ""),
"\\[note[0-9]{1,2}\\]", ""))) + 2 * (table_info$ncol - 1)
footer <- ""
for (i in 1:count.label) {
label.wrap <- strwrap(label[i], table.width)
footer <- paste0(footer, "\\\\multicolumn{", table_info$ncol,
"}{l}{\\\\textsuperscript{", ids[i], "} ",
label.wrap[1], "}\\\\\\\\\n")
if (length(label.wrap) > 1) {
for (j in 2:length(label.wrap)) {
footer <- paste0(footer, "\\\\multicolumn{", table_info$ncol,
"}{l}{", label.wrap[j], "}\\\\\\\\\n")
}
}
}
export <- gsub(table_info$end_tabular,
paste0(footer, "\\\\end{", table_info$tabular, "}"),
export)
}
}
}
# HTML Tables -------------------
if (attr(input, "format") == "html") {
# Clean the entry for labels
table_info <- magic_mirror(input)
if (escape) {
label <- escape_html(label)
}
# Replace in-table notation with appropriate symbol
for (i in 1:count.intablenote) {
export <- sub("\\[note\\]",
paste0("<sup>", ids.intable[i], "</sup>"),
export)
}
# Fix extra in table notation
for (i in extra.notation) {
export <- gsub(paste0("\\[note", i, "\\]"),
paste0("<sup>", ids.intable[i], "</sup>"),
export)
}
# Build footer
footer <- "<tfoot>\n"
for (i in 1:count.label) {
footer <- paste0(footer, "<tr>\n<td style = 'padding: 0; border:0;' ",
"colspan='100%'><sup>", ids[i],"</sup> ",
label[i], "</td>\n</tr>\n")
}
footer <- paste0(footer, "</tfoot>\n")
# Paste footer to the table
export[1] <- gsub("</tbody>\n", paste0("</tbody>\n", footer), export[1])
}
attr(export, "kable_meta") <- table_info
return(export)
}