Indeed! Great stuff Michael.
I suppose that error ("Error in loadNamespace(name) : there is no
package called ‘xts’") is yet another valid bug (sigh), if you wouldn't
mind filing please Sam.
Thanks,
Matthew
On 24.04.2013 02:16, Eduard Antonyan wrote:
This is great, a lot of cool stuff in one post!
On Apr 23, 2013, at 7:42 PM, Michael Nelson
<[email protected]> wrote:
From the help for data.table::last
If x is a data.table, the last row as a one row data.table.
Otherwise, whatever xts::last returns.
calling lapply(.SD, last) will call last on each column in .SD.
Columns within a data.table aren't data.tables thus `xts::last` is
called. xts is on the suggests list for data.table,
you could use
install.packages('data.table, dependencies = 'Suggests')
or manually installed xts.
OR
frame[, last(.SD), by = id]
would work without needing xts
as would
frame[, .SD[.N], by = id]
or without having to construct .SD (which is time consuming)
frame[frame[, .I[.N],by = id]$V1]
or
setkey(frame, id)
frame[unique(id), mult = 'last']
________________________________________
From: [email protected]
[[email protected]] on behalf of Sam
Steingold [[email protected]]
Sent: Wednesday, 24 April 2013 7:57 AM
To: [email protected]
Subject: [datatable-help] there is no package called ‘xts’
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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11.0.11300000
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