R - Conditional row highlighting in HTML table created using xtable or kable

Question

I\'m pretty much a beginner at programmatically formatting R output, but I\'ve got a basic understanding of knitr, xtable, Markdown, and Pandoc\'s

Answer 1

I've played around a good amount with formatting RMarkdown documents.

Since RMarkdown gets converted to LaTeX before the end PDF is generated, you can pass arguments that would work in LaTeX to RMarkdown. So, adding

header-includes:
  - \usepackage{xcolor}

in the heading of the RMarkdown document, and then adding something like

for(i in seq(1, nrow(yourDataframe), by = 2)){
  yourDataframe[i, ] <- paste0("\\color{purple}", yourDataframe[i, ])
  row.names(yourDataframe)[i] <- paste0("\\color{purple}", row.names(yourDataframe)[i])
}

will get you purple (or whatever color specified and allowed in the xcolor LaTeX package) entries in every other row of your table. Just another way to emphasize entries that isn't the base bold or italics given.

This isn't row highlighting, but could give you further customizable options.

*Tested with the pander package.

**You'll need to convert any factor columns to character columns for this method.

Answer 2

Here is a solution using ReporteRs:

set.seed(123)
df <- data.frame(id = sample(1:100, 20, replace = TRUE),
  inputval = sample(seq(0, 1, by=0.01), 20, replace = TRUE),
  outcome  = sample(1:4, 20, replace = TRUE))

library( ReporteRs )
library( magrittr )

# create and format table
myft = df %>% FlexTable() %>% 
  setRowsColors( df$outcome == 1, 'magenta') %>% 
  setFlexTableWidths( c( 1, 1, 1) )

# create an html doc and send myft into
doc = bsdoc() %>% addFlexTable( myft )

# write the html file in a new dir
writeDoc( doc, "example_out/df.html")

Answer 3

Here is a solution using Gmisc::htmlTable

set.seed(123)
df <- data.frame(id       = sample(1:100, 20, replace = TRUE),
                 inputval = sample(seq(0, 1, by=0.01), 20, replace = TRUE),
                 outcome  = sample(1:4, 20, replace = TRUE))

cols <- with(df, ifelse(outcome == 1, 'magenta', 'white'))

library(Gmisc)
htmlTable(as.matrix(df), altcol = cols, 
          rgroup = '', n.rgroup = rep(1, length(cols)))

EDIT

Since htmlTable has since been moved to the package, htmlTable, and is no longer in Gmisc >= 1.0, the new way to do this would be

library('htmlTable')
htmlTable(as.matrix(df), col.rgroup = cols)

which also gives:

and your markdown code would simply be

```{r, results='asis'}
htmlTable(as.matrix(df), altcol = cols, 
          rgroup = '', n.rgroup = rep(1, length(cols)))
```

And my .Rmd would look like:

---
output: 
  html_document:
    css: ~/knitr.css
---

```{r, results='asis', message=FALSE}
set.seed(123)
df <- data.frame(id       = sample(1:100, 20, replace = TRUE),
                 inputval = sample(seq(0, 1, by=0.01), 20, replace = TRUE),
                 outcome  = sample(1:4, 20, replace = TRUE))

cols <- with(df, ifelse(outcome == 1, 'magenta', 'white'))

library(Gmisc)
htmlTable(as.matrix(df), altcol = cols, 
          rgroup = '', n.rgroup = rep(1, length(cols)))
```

Answer 4

Well, not using colors (as not supported by markdown), but you can highlight cells/rows/columns of the table with pandoc.table and the general pander method by using bold or italics font face:

> library(pander)
> emphasize.rows(which(df$outcome == 2))
> pander(df)

-------------------------
 id   inputval   outcome 
---- ---------- ---------
 29     0.89        1    

*79*   *0.69*      *2*   

*41*   *0.64*      *2*   

*89*    *1*        *2*   

 95     0.66        1    

 5      0.71        1    

 53     0.54        1    

*90*   *0.6*       *2*   

*56*   *0.29*      *2*   

 46     0.14        4    

 96     0.97        1    

*46*   *0.91*      *2*   

 68     0.69        4    

 58     0.8         1    

 11     0.02        3    

 90     0.48        1    

 25     0.76        1    

 5      0.21        4    

 33     0.32        4    

*96*   *0.23*      *2*   
-------------------------