Basics of the sjt Table Functions

Daniel Lüdecke

2017-10-19

This vignette describes some basic features of all sjt functions from the sjPlot package. These functions create HTML table outputs.

Printing HTML tables

Before starting, we need to load the required packages and sample data.

# load packages
library(sjPlot)
library(sjmisc)
library(dplyr)
# load sample data set.
data(efc)

All sjt functions create a HTML page with the data table. This table, by default, is opened in the viewer pane of your IDE (in case you’re using an IDE which also supports the viewer pane, see parameter use.viewer for details). If a viewer pane is not available, the created HTML output is saved as temporary file and opened in your default webbrowser. The temporary files are deleted after your R session ends.

Copying table output to office or word processors

Export table as HTML file to open in word processors

You can save the HTML page as file for further usage by specifying the file parameter. The saved HTML file can be opened by word processors like LibreOffice or Microsoft Office.

Drag and drop from browser or RStudio viewer pane

You can directly drag and drop a table from the RStudio viewer pane oder browser into your word processor. Simply select the complete table with your mouse and drag it into office.

Character encoding

In some cases, you may have to specify a character encoding in order to get proper labels in the HTML tables. If you face problems with correctly displaying labels, use the encoding parameter to change the character encoding. This value dependes on your region where you live. Following example, which works for western European countries, is the default behaviour of all sjt-functions:

# don't need to do this, because all sjt-functions
# use this code as default encoding-detection
if (.Platform$OS.type == "unix") 
  encoding <- "UTF-8" 
else 
  encoding <- "Windows-1252"

sjt.frq(efc$e15relat, encoding = encoding)

This example first detects your operating system and then chooses the associated character encoding, which is used in the HTML file. If this does not work for you, you have to use the encoding parameter.

Knitr integration of HTML tables

sjPlot provides a print-method for HTML-tables to use in knitr-documents, so you can use the sjt-functions inside code chunks in knitr-rmarkdown files. The HTML-table will be printed to the knitr-document ‘as is’:

sjt.frq(efc$e42dep)
elder’s dependency
value N raw % valid % cumulative %
independent 66 7.27 7.33 7.33
slightly dependent 225 24.78 24.97 32.30
moderately dependent 306 33.70 33.96 66.26
severely dependent 304 33.48 33.74 100.00
missings 7 0.77
total N=908 · valid N=901 · x̄=2.94 · σ=0.94

This also works for table-outputs from sjtab(). For instance, you can easily create multiple tables from grouped data frames.

efc %>% 
  group_by(e16sex, c172code) %>% 
  select(e16sex, c172code, e42dep) %>% 
  sjtab()
elder’s gender: male
carer’s level of education: low level of education
value N raw % valid % cumulative %
independent 5 6.25 6.25 6.25
slightly dependent 16 20.00 20.00 26.25
moderately dependent 28 35.00 35.00 61.25
severely dependent 31 38.75 38.75 100.00
missings 0 0.00
total N=80 · valid N=80 · x̄=3.06 · σ=0.92

 

elder’s gender: male
carer’s level of education: intermediate level of education
value N raw % valid % cumulative %
independent 15 9.62 9.62 9.62
slightly dependent 39 25.00 25.00 34.62
moderately dependent 59 37.82 37.82 72.44
severely dependent 43 27.56 27.56 100.00
missings 0 0.00
total N=156 · valid N=156 · x̄=2.83 · σ=0.94

 

elder’s gender: male
carer’s level of education: high level of education
value N raw % valid % cumulative %
independent 1 2.33 2.33 2.33
slightly dependent 13 30.23 30.23 32.56
moderately dependent 18 41.86 41.86 74.42
severely dependent 11 25.58 25.58 100.00
missings 0 0.00
total N=43 · valid N=43 · x̄=2.91 · σ=0.81

 

elder’s gender: female
carer’s level of education: low level of education
value N raw % valid % cumulative %
independent 7 7.07 7.07 7.07
slightly dependent 25 25.25 25.25 32.32
moderately dependent 33 33.33 33.33 65.66
severely dependent 34 34.34 34.34 100.00
missings 0 0.00
total N=99 · valid N=99 · x̄=2.95 · σ=0.94

 

elder’s gender: female
carer’s level of education: intermediate level of education
value N raw % valid % cumulative %
independent 30 8.57 8.57 8.57
slightly dependent 96 27.43 27.43 36.00
moderately dependent 104 29.71 29.71 65.71
severely dependent 120 34.29 34.29 100.00
missings 0 0.00
total N=350 · valid N=350 · x̄=2.90 · σ=0.98

 

elder’s gender: female
carer’s level of education: high level of education
value N raw % valid % cumulative %
independent 4 3.54 3.54 3.54
slightly dependent 26 23.01 23.01 26.55
moderately dependent 44 38.94 38.94 65.49
severely dependent 39 34.51 34.51 100.00
missings 0 0.00
total N=113 · valid N=113 · x̄=3.04 · σ=0.85

 

Note that this does not properly work for PDF-documents, but only if the output of the rmarkdown-file is HTML.

Customizing table output with the CSS parameter

The table output is in in HTML format. The table style (visual appearance) is formatted using Cascading Style Sheets. If you are a bit familiar with these topics, you can easily customize the appearance of the table output.

Many table elements (header, row, column, cell, summary row, first row or column…) have CSS-class attributes, which can be used to change the table style. Since each sjt function has different table elements and thus different class attributes, you first need to know which styles can be customized.

Retrieving customizable styles

Each sjt function invisibly returns several values. The return value page.style contains the style information for the HTML table. You can print this style sheet to console using the base R cat() function:

cat(sjt.frq(efc$e42dep, no.output = TRUE)$page.style)
#> <style>
#> html, body { background-color: white; }
#> table { border-collapse:collapse; border:none; }
#> .thead { border-top:double; text-align:center; font-style:italic; font-weight:normal; padding-left:0.2cm; padding-right:0.2cm; }
#> .tdata { padding:0.2cm; }
#> .summary { text-align:right; font-style:italic; font-size:0.9em; padding-top:0.1cm; padding-bottom:0.1cm; }
#> .arc { background-color:#eaeaea; }
#> .qrow { border-bottom: 1px solid #cc3333; }
#> .mdrow { font-weight:bolder; font-style:italic; color:#993333; }
#> .abstand { margin-bottom: 2em; }
#> .lasttablerow { border-top:1px solid; border-bottom:double; }
#> .firsttablerow { border-bottom:1px solid; }
#> .leftalign { text-align:left; }
#> .centeralign { text-align:center; }
#> caption { font-weight: bold; text-align:left; }
#> .firsttablecol {  }
#> </style>

The HTML code is obtained by using the page.content return value. Since the sjt.frq() function allows to plot multiple tables at once, this function returns a list of HTML tables as page.content.list. The following code prints the HTML code of the table to the R console:

cat(sjt.frq(efc$e42dep, no.output = TRUE)$page.content.list[[1]])
# not that other sjt-functions don't return a page.content-list, but
# just '$page.content'...

Now you can see which table elements are associated with which CSS class attributes. If you compare the page.style with the related page.content, you see that not all style attributes are used:

Customizing table output with the CSS parameter

You can customize the table output with the CSS parameter. This parameter requires a list of attributes, which follow a certain pattern:

  1. each attributes needs a css. prefix
  2. followed by the class name (e.g. caption, thead, centeralign, arc etc.)
  3. equal-sign
  4. the CSS format (in (single) quotation marks)
  5. the CSS format must end with a colon (;)

Example:

sjt.frq(
  efc$e42dep, 
  CSS = list(css.centeralign = 'text-align: left;', 
             css.caption = 'font-weight: normal; font-style: italic;', 
             css.firsttablecol = 'font-weight: bold;', 
             css.lasttablerow = 'border-top: 1px solid; border-bottom: none;', 
             css.summary = 'color: blue;')
)
elder’s dependency
value N raw % valid % cumulative %
independent 66 7.27 7.33 7.33
slightly dependent 225 24.78 24.97 32.30
moderately dependent 306 33.70 33.96 66.26
severely dependent 304 33.48 33.74 100.00
missings 7 0.77
total N=908 · valid N=901 · x̄=2.94 · σ=0.94

In the above example, the summary-table row lost the original style and just became blue. If you want to keep the original style and just add additional style information, use the plus-sign (+) as initial character for the parameter attributes. In the following example, the summary row keeps its original style and is additionally printed in blue:

sjt.frq(efc$e42dep, CSS = list(css.summary = '+color: blue;'))
elder’s dependency
value N raw % valid % cumulative %
independent 66 7.27 7.33 7.33
slightly dependent 225 24.78 24.97 32.30
moderately dependent 306 33.70 33.96 66.26
severely dependent 304 33.48 33.74 100.00
missings 7 0.77
total N=908 · valid N=901 · x̄=2.94 · σ=0.94