
R version 3.1.1 (2014-07-10) -- "Sock it to Me"
Copyright (C) 2014 The R Foundation for Statistical Computing
Platform: x86_64-pc-linux-gnu (64-bit)

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> if (suppressPackageStartupMessages(requireNamespace("knitr", quietly = TRUE))) {
+     require(knitr)
+     knit("knitr.Rmd", quiet=TRUE)
+     cat(readLines("knitr.md"), sep="\n")
+ } else {
+     cat(readLines("knitr.Rout.mock", warn = FALSE), sep="\n")
+ }
Loading required package: knitr
Loading required package: data.table

```r
require(data.table)              # print?
DT = data.table(x=1:3, y=4:6)    # no
DT                               # yes
```

```
##    x y
## 1: 1 4
## 2: 2 5
## 3: 3 6
```

```r
DT[, z := 7:9]                   # no
print(DT[, z := 10:12])          # yes
```

```
##    x y  z
## 1: 1 4 10
## 2: 2 5 11
## 3: 3 6 12
```

```r
if (1 < 2) DT[, a := 1L]         # no
DT                               # yes
```

```
##    x y  z a
## 1: 1 4 10 1
## 2: 2 5 11 1
## 3: 3 6 12 1
```
Some text.

> 
> 
> proc.time()
   user  system elapsed 
  3.116   0.128   3.257 
