R markdown：以颜色打印 data.table 或矩阵的选定条目

Question

我有一个这样的 data.table：

my.data.table <- data.table(a = c(1,-2),
                            b = c(-3,4))

使用 R markdown to PDF (latex)，我如何打印 my.data.table 以便所有负数都以红色打印，而正数和列标题保持黑色？矩阵的类似解决方案也可以。

Answer 1

您可以按照official documentation 尝试kableExtra 解决方案：

---
title: "kableExtra with cell_spec"
author: "bttomio"
date: "3/26/2021"
output: pdf_document
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
library(kableExtra)
library(data.table)
```

# data.table

```{r echo=F}
my.data.table <- data.table(a = c(1,-2),
                            b = c(-3,4))

my.data.table$a <- cell_spec(my.data.table$a, 
                            color = ifelse(my.data.table$a>0, "black", "red"))

my.data.table$b <- cell_spec(my.data.table$b, 
                            color = ifelse(my.data.table$b>0, "black", "red"))

kbl(my.data.table, 'latex', booktabs = T, escape = F)
```

# matrix

```{r echo=F}
my.data.table <- matrix(c(1,-2,-3,4), nrow = 2,
                        dimnames = list(c("1", "2"), c("a", "b")))

my.data.table[,1] <- cell_spec(my.data.table[,1], 
                            color = ifelse(my.data.table[,1]>0, "black", "red"))

my.data.table[,2] <- cell_spec(my.data.table[,2], 
                            color = ifelse(my.data.table[,2]>0, "black", "red"))

kbl(my.data.table, 'latex', booktabs = T, escape = F)
```

-输出