R Markdown Table 1000 separator - r-markdown

Question

I am trying to publish a table with 1000 separators and I am not having any luck with it. I followed the link here: Set global thousand separator on knitr but am not having much success.
My sample dataset is here: https://goo.gl/G7sZhr
The RMarkdown code is here:
---
title: "Table Example"
author: "Krishnan Viswanathan"
date: "August 4, 2015"
output: html_document
---
Load Data
{r, results='asis', message = FALSE, tidy=TRUE}
load("i75_from_flow.RData")
library(data.table)
{r, results='asis', echo=FALSE,message = FALSE, tidy=TRUE}
i75_from_flow <- i75_from_flow[order(-Tons),]
knitr::kable(i75_from_flow)
However, when I include this chunk of code (knit_hook$set) in the RMarkdown document, i get errors.
```{r, results='asis', echo=FALSE,message = FALSE, tidy=TRUE}
i75_from_flow <- i75_from_flow[order(-Tons),]
knit_hooks$set(inline = function(x) {
prettyNum(x, big.mark=",")
})
knitr::kable(i75_from_flow)
```
Error:
# object knit_hooks not found.
Any insights on what I am doing wrong and how to fix this is much appreciated.
Thanks,
Krishnan

Answer 1

The easiest is to use the format arguments of the kable() function itself, where you can specify the big number mark like so:
kable(df, format.args = list(big.mark = ","))
So your example would look like:
```{r, results='asis', echo=FALSE,message = FALSE, tidy=TRUE}
i75_from_flow <- i75_from_flow[order(-Tons),]
knitr::kable(i75_from_flow, format.args = list(big.mark = ","))
```
without any need for knitr hooks.

Answer 2

What about using pander with bunch of options to fine-tune your markdown table:
> pander::pander(i75_from_flow, big.mark = ',')
----------------------------
ORIGFIPS TERMFIPS Tons
---------- ---------- ------
12,023 12,117 5,891
12,119 12,105 4,959
12,001 12,057 3,585
12,001 12,113 3,083
12,047 12,047 1,517
----------------------------

Answer 3

The reason that the knit_hooks object is not found is that you either need to load the knitr package or use the knitr:: prefix in order to set the knit_hooks options. For example:
knitr::knit_hooks$set(inline = function(x) {
prettyNum(x, big.mark=",")
})