Using the flextable R package
2023-01-17
Chapter 1 Overview
The flextable package provides a framework for easily create tables for reporting and publications. Functions are provided to let users create tables, modify and format their content and define their content.
Tables can be embedded within:
- R Markdown documents with support for HTML, Word, PDF and PowerPoint documents.
- Microsoft Word or PowerPoint documents with package officer.
Tables can also be rendered as R plots or graphic files (png, pdf and jpeg).
1.1 Introduction
flextable
can easily create reporting table from data.frame
. You
can merge cells, add header rows, add footer rows, change any format
and specify how data should be displayed in cells. Tables content can also
contain mixed type of content, text and images.
The following table is an example of a flextable rendered in HTML.
ft <- flextable(airquality[ sample.int(10),])
ft <- add_header_row(ft,
colwidths = c(4, 2),
values = c("Air quality", "Time")
)
ft <- theme_vanilla(ft)
ft <- add_footer_lines(ft, "Daily air quality measurements in New York, May to September 1973.")
ft <- color(ft, part = "footer", color = "#666666")
ft <- set_caption(ft, caption = "New York Air Quality Measurements")
ft
Air quality |
Time |
||||
---|---|---|---|---|---|
Ozone |
Solar.R |
Wind |
Temp |
Month |
Day |
12 |
149 |
12.6 |
74 |
5 |
3 |
19 |
99 |
13.8 |
59 |
5 |
8 |
8 |
19 |
20.1 |
61 |
5 |
9 |
23 |
299 |
8.6 |
65 |
5 |
7 |
36 |
118 |
8.0 |
72 |
5 |
2 |
18 |
313 |
11.5 |
62 |
5 |
4 |
41 |
190 |
7.4 |
67 |
5 |
1 |
14.3 |
56 |
5 |
5 |
||
28 |
14.9 |
66 |
5 |
6 |
|
194 |
8.6 |
69 |
5 |
10 |
|
Daily air quality measurements in New York, May to September 1973. |
The main function is flextable
. Call the function with a data.frame
as argument. If you are using RStudio or another R GUI, the table will
be displayed in the Viewer panel or in your default browser.
flextable(world_phones)
year |
N.Amer |
Europe |
Asia |
S.Amer |
Oceania |
Africa |
Mid.Amer |
---|---|---|---|---|---|---|---|
1951 |
45 939 |
21 574 |
2 876 |
1 815 |
1 646 |
89 |
555 |
1956 |
60 423 |
29 990 |
4 708 |
2 568 |
2 366 |
1 411 |
733 |
1957 |
64 721 |
32 510 |
5 230 |
2 695 |
2 526 |
1 546 |
773 |
1958 |
68 484 |
35 218 |
6 662 |
2 845 |
2 691 |
1 663 |
836 |
1959 |
71 799 |
37 598 |
6 856 |
3 000 |
2 868 |
1 769 |
911 |
1960 |
76 036 |
40 341 |
8 220 |
3 145 |
3 054 |
1 905 |
1 008 |
1961 |
79 831 |
43 173 |
9 053 |
3 338 |
3 224 |
2 005 |
1 076 |
Why the table we have produced use font ‘Helvetica’ with color black and size 11 point? The formatting properties that were used are the default properties.
It is also using a simple formatting function to create the paragraphs of text that will be rendered in each cell.
If you want to change the default appearance
of the tables, you can use the set_flextable_defaults
function.
set_flextable_defaults(
font.size = 10, theme_fun = theme_vanilla,
padding = 6,
background.color = "#EFEFEF")
flextable(world_phones)
year |
N.Amer |
Europe |
Asia |
S.Amer |
Oceania |
Africa |
Mid.Amer |
---|---|---|---|---|---|---|---|
1951 |
45 939 |
21 574 |
2 876 |
1 815 |
1 646 |
89 |
555 |
1956 |
60 423 |
29 990 |
4 708 |
2 568 |
2 366 |
1 411 |
733 |
1957 |
64 721 |
32 510 |
5 230 |
2 695 |
2 526 |
1 546 |
773 |
1958 |
68 484 |
35 218 |
6 662 |
2 845 |
2 691 |
1 663 |
836 |
1959 |
71 799 |
37 598 |
6 856 |
3 000 |
2 868 |
1 769 |
911 |
1960 |
76 036 |
40 341 |
8 220 |
3 145 |
3 054 |
1 905 |
1 008 |
1961 |
79 831 |
43 173 |
9 053 |
3 338 |
3 224 |
2 005 |
1 076 |
speed |
dist |
---|---|
4 |
2 |
4 |
10 |
7 |
4 |
7 |
22 |
8 |
16 |
9 |
10 |
The package also provides a set of functions to easily create some tables:
-
as_flextable()
allows to transform R models into a table ready for export -
proc_freq()
allows to create a contingency table like the PROC FREQ of SAS. -
tabulator()
creates a table whose layout is showing dimensions of
aggregations across rows and columns. -
summarizor()
provides statistical summaries as pretty tables.
Finally, it allows to automate the production of simple tables in
‘R Markdown’ for the display of ‘data.frame’ and models (lm, glm,
gam, lme, lmer, kmeans and few other one) with functions
use_df_printer()
and use_model_printer()
.
1.2 Other ressources
1.2.1 Function reference
Function reference (manuals) is available here: https://davidgohel.github.io/flextable/reference/index.html
These manuals are also available when using R as usual help pages.
1.2.2 Gallery
You can also consult the gallery of examples which is available here.It is composed of examples with codes to allow their reproduction.
The gallery is available here: https://ardata.fr/en/flextable-gallery/
1.2.3 Cheat sheet
A cheat sheet has been written by Clémentine Jager and available here: Flextable cheat sheet
1.3 Walkthrough: simple example
flextable has been designed to allow the construction of simple and complex tables. A set of functions will allow you to change colors, fonts, add headers and many other things to give you the possibility to build the tables that fit your needs.
Let’s have a step by step simple demo.
First, the flextable has to be created.
am |
carb |
gear |
mpg |
drat |
---|---|---|---|---|
1 |
4 |
4 |
21.0 |
3.90 |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
1 |
4 |
22.8 |
3.85 |
0 |
1 |
3 |
21.4 |
3.08 |
0 |
2 |
3 |
18.7 |
3.15 |
0 |
1 |
3 |
18.1 |
2.76 |
Optional argument col_keys
is used to only display a subset of columns.
Many sugar functions can be used to format flextables: bg()
, fontsize()
, italic()
, bold()
, color()
, padding()
…
flextable is separating the data and the display of the data. It makes possible to do conditional formatting. Conditional formatting can be made by using the selector arguments. All formatting functions are accepting selector arguments.
myft <- italic(myft, j = 3)
myft <- color(myft, ~ drat > 3.5, ~ drat, color = "red")
myft <- bold(myft, ~ drat > 3.5, ~ drat, bold = TRUE)
myft
am |
carb |
gear |
mpg |
drat |
---|---|---|---|---|
1 |
4 |
4 |
21.0 |
3.90 |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
1 |
4 |
22.8 |
3.85 |
0 |
1 |
3 |
21.4 |
3.08 |
0 |
2 |
3 |
18.7 |
3.15 |
0 |
1 |
3 |
18.1 |
2.76 |
Table layout can be modified. One can add or change header/footer rows, change cells height and width and merge cells.
myft <- add_header_row(
x = myft, values = c("some measures", "other measures"),
colwidths = c(3, 2))
myft <- align(myft, i = 1, part = "header", align = "center")
myft
some measures |
other measures |
|||
---|---|---|---|---|
am |
carb |
gear |
mpg |
drat |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
1 |
4 |
22.8 |
3.85 |
0 |
1 |
3 |
21.4 |
3.08 |
0 |
2 |
3 |
18.7 |
3.15 |
0 |
1 |
3 |
18.1 |
2.76 |
Functions theme_
are sugar functions whose role is to apply a set
of formatting instructions to a flextable.
myft <- theme_vanilla(myft)
myft
some measures |
other measures |
|||
---|---|---|---|---|
am |
carb |
gear |
mpg |
drat |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
4 |
4 |
21.0 |
3.90 |
1 |
1 |
4 |
22.8 |
3.85 |
0 |
1 |
3 |
21.4 |
3.08 |
0 |
2 |
3 |
18.7 |
3.15 |
0 |
1 |
3 |
18.1 |
2.76 |