Comma separator for numbers in R?

Is there a function in R to display large numbers separated with commas?

i.e., from 1000000 to 1,000,000.

You can try either format or prettyNum, but both functions return a vector of characters. I'd only use that for printing.

> prettyNum(12345.678,big.mark=",",scientific=FALSE)
[1] "12,345.68"
> format(12345.678,big.mark=",",scientific=FALSE)
[1] "12,345.68"

---

EDIT: As Michael Chirico says in the comment:

Be aware that these have the side effect of padding the printed strings with blank space, for example:

> prettyNum(c(123,1234),big.mark=",")
[1] "  123" "1,234"

Add trim=TRUE to format or preserve.width="none" to prettyNum to prevent this:

> prettyNum(c(123,1234),big.mark=",", preserve.width="none")
[1] "123"   "1,234"
> format(c(123,1234),big.mark=",", trim=TRUE)
[1] "123"   "1,234"

See ?format:

> format(1e6, big.mark=",", scientific=FALSE)
[1] "1,000,000" 
>   

The other answers posted obviously work - but I have always used

library(scales)    
label_comma()(1000000)

I think Joe's comment to MatthewR offers the best answer and should be highlighted:

As of Sept 2018, the [scales](https://www.tidyverse.org/blog/2018/08/scales-1-0-0/ "Tidyverse: Scales 1.0.0") package (part of the Tidyverse) does exactly this:

> library(scales)

> x <- 10e5
> comma(x)

[1] "1,000,000"

The scales package appears to play very nicely with ggplot2, allowing for fine control of how numerics are displayed in plots and charts.