user3022875 user3022875 - 5 days ago 4
R Question

how can xtable do cell coloring

I have this table in a .RMD file and I would like to render in PDF with conditional formatting. Currently I am using pandoc. How can this be done with xtable?

table = data.frame(category = c("A","B","C"), groupA = c(.2,.3,.5), groupB= c(.6,.7,.9))
table
pandoc.table(table,split.table = Inf,keep.line.breaks = TRUE)

----------------------------
category groupA groupB
---------- -------- --------
A 0.2 0.6

B 0.3 0.7

C 0.5 0.9
----------------------------


How can I color the cells of the "groupA" and "groupB" columns with conditional formatting like:

>0 and <= .2 = "green"
>.2 and <= .3 = "red"
>.3 and <= .4 = "blue"
>.4 and <= .5 = "orange"
>.5 and <= .6 = "yellow"
>.6 and <= .7 = "black"
>.7 and <= .8 = "brown"
>.8 = "white"

Answer

You can wrap the relevant table entries n latex code (from here), and then sanitize the xtable results.

Example:

---
header-includes:
   - \usepackage{xcolor, colortbl}
output:
    pdf_document
---

```{r, results="asis"}

library(xtable)
# Your data
tab = data.frame(category = c("A","B","C"), groupA = c(.2,.3,.5), groupB= c(.6,.7,.9))

# Function to cut your data, and assign colour to each range
f <- function(x) cut(x, c(0, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, Inf), 
                      labels=c("green", "red", "blue", "orange", "yellow", "purple", "brown", "white"),
                      include.lowest = FALSE, right = TRUE)

# Apply function to columns: this overwrites your data
tab[c("groupA", "groupB")] <- lapply(tab[c("groupA", "groupB")], function(x)
                                            paste0("\\cellcolor{", f(x), "}", x))
# Sanitise output 
print(xtable(tab), sanitize.text.function = identity)
```

which produces

enter image description here

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