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.
flextable objects can be rendered in HTML format but also in Microsoft Word and PowerPoint documents.
Two functions are provided:
flextable function is producing flexible tables where each cell can contain several chunks of text with their own set of formatting properties (bold, font color, etc.). Function
display lets customise text of cells (See display function).
regulartable function has been written because the first one is ressource consumming. The main difference is that it is producing tables where cells can contain only one chunk of text with its own set of formatting properties. Function
set_formatter is customizing text of cells.
Note also that
regulartable supports strange variable names (with percent symbols, with spaces, etc.) and
flextable does not support them.
The following table is made with
regulartableand dataset data:
data <- iris[c(1:3, 51:53, 101:104),]
A flextable is an object that will produce a reporting table from a
data.frame object. Any formatting property related to text, paragraphs, cells in the table can be modified. Content can also be customized.
Columns to display are by default all columns of the data.frame but can be choosen from a subset of existing columns and also unexisting columns.
Unexisting columns are containing blanks by default but this content can be customized.
A flextable is containing two parts, one for header rows and one for body rows. By default, there is only one header row containing the names of the data.frame. The body part is containing data from the data.frame.
A cell is made of one single paragraph of text. The paragraph can contain several chunks of text with different formatting properties but newlines are always ignored.
The dimensions of the flextable elements, widths of columns and heights of rows, are always defined. Beeing able to define the exact size necessary to display data on a single line is a key concept. See functions
Let’s have a step by step demo. First create a regulartable and change header font in bold.
library(flextable)library(officer)myft <- regulartable(head(mtcars),col_keys = c("am", "carb", "gear", "mpg", "drat" ))myft
flextable or regulartable function:
flextable create a flextable object based on input data. Optional argument
col_keys is used to only display a subset of columns.
Let’s keep it simple and apply a theme to format the whole table. Functions
theme_ are sugar functions whose role is to apply a set of formatting instructions to a flextable. For example,
theme_vanilla set specific borders, right align paragraphs and make headers bold.
myft <- theme_vanilla(myft)myft
To learn more, see article about layouts.
Table layout can be modified. One can add or change header/footer rows, change cells height and width and merge cells. Also, there is an important function named
autofit (it adjusts widths and heights regarding to text widths and heights).
We will use
merge_v() to merge identical consecutive cells of columns “carb” and “am”.
myft <- merge_v(myft, j = c("am", "carb") )myft
set_header_labels() set labels:
myft <- set_header_labels( myft, carb = "# carb." )myft <- width(myft, width = .75) # set width of all columns to .75 inmyft
autofit() adjust widths and heights of cells. This should be the last operation as some operations make columns wider, e.g. changing font size, changing font weight.
autofit makes sure that any content is displayed as a single line of text.
myft <- autofit(myft)myft
To learn more, see article about format.
myft <- italic(myft, j = 1)myft <- bg(myft, bg = "#C90000", part = "header")myft <- color(myft, color = "white", part = "header")myft
Conditional formatting can be made by using the selector arguments. All formatting functions are accepting selector arguments.
myft <- color(myft, ~ drat > 3.5, ~ drat, color = "red")myft <- bold(myft, ~ drat > 3.5, ~ drat, bold = TRUE)myft <- autofit(myft)myft
When working in RStudio, flextable will be printed in the rstudio viewer pane.
flextables can be inserted in R Markdown documents; HTML and Word output are managed with method
flextable object in the rmarkdown’s chunk as demonstrated in this document (…generated from an R Markdown document).
Note that pandoc 2.0 required for flextable rendering in docx with
officer package is required to create a PowerPoint or Word document.
The following is producing a PowerPoint document:
ft <- regulartable(head(mtcars))ft <- theme_booktabs(ft)ft <- autofit(ft)ppt <- read_pptx()ppt <- add_slide(ppt, layout = "Title and Content", master = "Office Theme")ppt <- ph_with_flextable(ppt, value = ft, type = "body")print(ppt, target = "assets/pptx/example.pptx")
The following is producing a Word document:
doc <- read_docx()doc <- body_add_flextable(doc, value = ft)print(doc, target = "assets/docx/example.docx")