.Rmd中使用的R - kable（）不会在笔记本中显示输出(R - kable() used in .Rmd does not show output in notebook)

 我刚开始使用kableExtra库来使我的表格在PDF输出中看起来更好。 
 但是当我在R Notebook文件中使用kable()函数时，它不显示输出。 相反，我看到输出应该是一个很大的空白区域。 
 这是一个截图： 
 
  当我把文件Knit成PDF时，我可以看到输出。 
 这是一个截图： 
  
 有什么办法可以使输出出现在Notebook和PDF中？ 这是我的代码： 
 
---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
---

```{r  message=FALSE, warning=FALSE}
library(knitr)
library(kableExtra)
library(dplyr)
#plot(cars)
```

```{r}
 cars %>% 
  slice(1:10) %>% 
  select(speed, dist) %>% 
  kable(format = "latex", booktabs = T) %>% 
  column_spec(column = 1:2, width = "0.5in")

```

I just started using kableExtra library to make my tables look better in the PDF output.
 But when I use kable() function in R Notebook file, it does not show the output. Instead I see a large white space where the output should be.
 Here is a screenshot: 
 
 When I Knit the file to PDF I can see the output.
 Here is a screenshot:
 
 Is there a way I can make the output appear both in the Notebook and PDF? Here is my code:
 
---
title: "R Notebook"
output:
  pdf_document: default
  html_notebook: default
---

```{r  message=FALSE, warning=FALSE}
library(knitr)
library(kableExtra)
library(dplyr)
#plot(cars)
```

```{r}
 cars %>% 
  slice(1:10) %>% 
  select(speed, dist) %>% 
  kable(format = "latex", booktabs = T) %>% 
  column_spec(column = 1:2, width = "0.5in")

```