[datatable-help] there is no package called ‘xts’

[Sam Steingold]

Hi,
I got this:

> dt <- frame[, lapply(.SD, last) ,by=id]
Finding groups (bysameorder=TRUE) ... done in 0.126secs. bysameorder=TRUE and o__ is length 0
Optimized j from 'lapply(.SD, last)' to 'list(last(country), last(language), last(browser), last(platform), last(uatype), last(behavior))'
Starting dogroups ... Error in loadNamespace(name) : there is no package called ‘xts’
Calls: [ -> [.data.table -> last -> :: -> getExportedValue -> asNamespace -> getNamespace -> tryCatch -> tryCatchList -> tryCatchOne -> <Anonymous>
>

the help for last does mention xts, but I don't have it installed.
do I need to?

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