# Legacy or Unrecommended Features

#### Hao Zhu

#### 2026-07-04

This document includes documentations for legacy/unrecommended features in this package.

Unless there are significant differences between HTML/LaTeX, I will only keep one copy of documentation in HTML here since most of the functions in this packages share a very similar interface between their HTML and LaTeX ends.

    library(kableExtra)
    dt <- mtcars[1:5, 1:6]

# Unrecommended Features

## add_footnote

As the first function written in this package, the design of the `add_footnote` function is not flexible enough to introduce new features to this function. So I redesigned the footnote part and created the `footnote()` function. `add_footnote` will still be there for a while and be maintained because of its unique feature to add page footnote to longtables.

Here are the old documentation for `add_footnote`.

### Notation systems

You can also use `add_footnote()` function from this package. You will need to supply a character vector with each element as one footnote. You may select from `number`, `alphabet` and `symbol` for different types of notations. Example are listed below.

#### Alphabet

    kable(dt, "html") %>%
      kable_styling("striped") %>%
      add_footnote(c("Footnote 1", "Have a good day."), notation = "alphabet")

| mpg | cyl | disp | hp | drat | wt
--- | --- | --- | --- | --- | --- | ---
Mazda RX4 | 21.0 | 6 | 160 | 110 | 3.90 | 2.620
Mazda RX4 Wag | 21.0 | 6 | 160 | 110 | 3.90 | 2.875
Datsun 710 | 22.8 | 4 | 108 | 93 | 3.85 | 2.320
Hornet 4 Drive | 21.4 | 6 | 258 | 110 | 3.08 | 3.215
Hornet Sportabout | 18.7 | 8 | 360 | 175 | 3.15 | 3.440
a Footnote 1
b Have a good day.

#### Number

    kable(dt, "html") %>%
      kable_styling("striped") %>%
      add_footnote(c("Footnote 1", "Have a good day."), notation = "number")

| mpg | cyl | disp | hp | drat | wt
--- | --- | --- | --- | --- | --- | ---
Mazda RX4 | 21.0 | 6 | 160 | 110 | 3.90 | 2.620
Mazda RX4 Wag | 21.0 | 6 | 160 | 110 | 3.90 | 2.875
Datsun 710 | 22.8 | 4 | 108 | 93 | 3.85 | 2.320
Hornet 4 Drive | 21.4 | 6 | 258 | 110 | 3.08 | 3.215
Hornet Sportabout | 18.7 | 8 | 360 | 175 | 3.15 | 3.440
1 Footnote 1
2 Have a good day.

#### Symbol

    kable(dt, "html") %>%
      kable_styling("striped") %>%
      add_footnote(c("Footnote 1", "Footnote 2", "Footnote 3"), notation = "symbol")

| mpg | cyl | disp | hp | drat | wt
--- | --- | --- | --- | --- | --- | ---
Mazda RX4 | 21.0 | 6 | 160 | 110 | 3.90 | 2.620
Mazda RX4 Wag | 21.0 | 6 | 160 | 110 | 3.90 | 2.875
Datsun 710 | 22.8 | 4 | 108 | 93 | 3.85 | 2.320
Hornet 4 Drive | 21.4 | 6 | 258 | 110 | 3.08 | 3.215
Hornet Sportabout | 18.7 | 8 | 360 | 175 | 3.15 | 3.440
* Footnote 1
† Footnote 2
‡ Footnote 3

### In-table markers

By design, `add_footnote()` will transform any `[note]` to in-table footnote markers.

    kable(dt, "html", caption = "Demo Table[note]") %>%
      kable_styling("striped") %>%
      add_header_above(c(" ", "Group 1[note]" = 3, "Group 2[note]" = 3)) %>%
      add_footnote(c("This table is from mtcars",
                     "Group 1 contains mpg, cyl and disp",
                     "Group 2 contains hp, drat and wt"),
                   notation = "symbol")

Demo Table*
| Group 1† | Group 2‡
--- | --- | ---
| mpg | cyl | disp | hp | drat | wt
Mazda RX4 | 21.0 | 6 | 160 | 110 | 3.90 | 2.620
Mazda RX4 Wag | 21.0 | 6 | 160 | 110 | 3.90 | 2.875
Datsun 710 | 22.8 | 4 | 108 | 93 | 3.85 | 2.320
Hornet 4 Drive | 21.4 | 6 | 258 | 110 | 3.08 | 3.215
Hornet Sportabout | 18.7 | 8 | 360 | 175 | 3.15 | 3.440
* This table is from mtcars
† Group 1 contains mpg, cyl and disp
‡ Group 2 contains hp, drat and wt