Adding tables to posts

The most convenient way to generate a table containing R output is the function knitr::kable(). Like figures, tables with captions will also be numbered and can be referenced in the text of your post. To do this, you will need to do two things:

1. Label the R code chunk used to produce the table
2. Use knitr::kable(caption = "look at this") to provide a table caption.

To reference the table in the text of your post, use the syntax \@ref(tab:chunk-label),¹ where chunk-label is the label of the chunk containing the R code that produces the table. The kable() function will automatically generate a label for a table environment, which is the prefix tab: plus the chunk label.

For example, the table label for a code chunk with the label foo will be tab:foo, and we use the syntax \@ref(tab:label) to reference the table in text. Table 1 is a simple example.

library(dplyr)
library(knitr)
ct <- mtcars[, 1:8] %>% 
  head(10) 
ct %>% 
  kable("html", caption = 'A table of the first 10 rows of the mtcars data.')

Table 1: A table of the first 10 rows of the mtcars data.

	mpg	cyl	disp	hp	drat	wt	qsec	vs
Mazda RX4	21.0	6	160.0	110	3.90	2.620	16.46	0
Mazda RX4 Wag	21.0	6	160.0	110	3.90	2.875	17.02	0
Datsun 710	22.8	4	108.0	93	3.85	2.320	18.61	1
Hornet 4 Drive	21.4	6	258.0	110	3.08	3.215	19.44	1
Hornet Sportabout	18.7	8	360.0	175	3.15	3.440	17.02	0
Valiant	18.1	6	225.0	105	2.76	3.460	20.22	1
Duster 360	14.3	8	360.0	245	3.21	3.570	15.84	0
Merc 240D	24.4	4	146.7	62	3.69	3.190	20.00	1
Merc 230	22.8	4	140.8	95	3.92	3.150	22.90	1
Merc 280	19.2	6	167.6	123	3.92	3.440	18.30	1

For some additional formatting options, you can also use the kableExtra package. Table 2 uses the kable_styling() function to center the table. Read the vignette for more options.

library(kableExtra)
ct %>% 
  kable("html", caption = 'This table is centered.') %>%
  kable_styling(position = "center")

Table 2: This table is centered.

	mpg	cyl	disp	hp	drat	wt	qsec	vs
Mazda RX4	21.0	6	160.0	110	3.90	2.620	16.46	0
Mazda RX4 Wag	21.0	6	160.0	110	3.90	2.875	17.02	0
Datsun 710	22.8	4	108.0	93	3.85	2.320	18.61	1
Hornet 4 Drive	21.4	6	258.0	110	3.08	3.215	19.44	1
Hornet Sportabout	18.7	8	360.0	175	3.15	3.440	17.02	0
Valiant	18.1	6	225.0	105	2.76	3.460	20.22	1
Duster 360	14.3	8	360.0	245	3.21	3.570	15.84	0
Merc 240D	24.4	4	146.7	62	3.69	3.190	20.00	1
Merc 230	22.8	4	140.8	95	3.92	3.150	22.90	1
Merc 280	19.2	6	167.6	123	3.92	3.440	18.30	1

Tables can also be formatted using the formattable package, in combination with knitr::kable() and the kableExtra package. Table 3 uses the color_tile() and color_bar() functions. Read this vignette for more options.

library(formattable)
ct %>% 
  mutate(mpg = color_tile("transparent", "lightpink")(mpg),
         hp = color_bar("lightseagreen")(hp)) %>%
  kable("html", escape = F, caption = 'This table is colored.') %>%
  kable_styling(position = "center") %>% 
  column_spec(4, width = "3cm") 

Table 3: This table is colored.

mpg	cyl	disp	hp	drat	wt	qsec	vs
21.0	6	160.0	110	3.90	2.620	16.46	0
21.0	6	160.0	110	3.90	2.875	17.02	0
22.8	4	108.0	93	3.85	2.320	18.61	1
21.4	6	258.0	110	3.08	3.215	19.44	1
18.7	8	360.0	175	3.15	3.440	17.02	0
18.1	6	225.0	105	2.76	3.460	20.22	1
14.3	8	360.0	245	3.21	3.570	15.84	0
24.4	4	146.7	62	3.69	3.190	20.00	1
22.8	4	140.8	95	3.92	3.150	22.90	1
19.2	6	167.6	123	3.92	3.440	18.30	1

To make an interactive table, see our post on adding HTML widgets using the DT package.