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rdata.tableggvis

ggvis and data.table conflict?

I am trying to run ggvis in combination with data.table, see code below. I get the following error:

Error in `:=`(mpg2, mpg/2) : 
  Check that is.data.table(DT) == TRUE. Otherwise, := and `:=`(...) 
  are defined for use     in j, once only and in particular ways. See help(":=").

If I run the line mtcars[ , mpg2 := mpg / 2] in the console there is no problem. So what is the problem? [I am still suspicious about the fact that both data.table and ggvis use :=. 

---
title: "Untitled"
output: html_document
runtime: shiny
---

```{r echo = FALSE}
library(ggvis)
library(data.table)

mtcars %>%
  ggvis(x = ~wt, y = ~mpg) %>%
  layer_points()

mtcars = data.table(mtcars)
mtcars[, mpg2 := mpg / 2]  # gives error message

# code below does not work as the line above throws an error

mtcars %>%
  ggvis(x = ~wt, y = ~mpg2) %>%
  layer_points()

```

data.table version 1.9.2

ggvis from github 0.3.0.9001 as CRAN version complained about missing knit_print.

Solution

  • I have updated to data.table 1.9.3 and everything works like it should now. Thanks!