Eric

let the data.frame be data.frame, and data.table be data.table.

5

Hi, Xiaodaign, Thanks for the great work. I noticed that, due to the legacy issue from some other package, the `data.frame` is more pleasible for `data.frame`, than `data.table`. What if...

第一个范例就跑不出来

7

```r library(stringr) library(XML) library(maps) surl