<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Nice! I don't see why not. It's a nice use of .EACHI. Perhaps you'd like to file it as a FR? It'd be easy to keep track then, for later, when Matt'll also have a look..</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <div id="bloop_sign_1404190669009587968" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">Arun</div></div> <div style="color:black"><br>From: <span style="color:black">Gabor Grothendieck</span> <a href="mailto:ggrothendieck@gmail.com">ggrothendieck@gmail.com</a><br>Reply: <span style="color:black">Gabor Grothendieck</span> <a href="mailto:ggrothendieck@gmail.com">ggrothendieck@gmail.com</a><br>Date: <span style="color:black">June 30, 2014 at 8:41:51 PM</span><br>To: <span style="color:black">Arunkumar Srinivasan</span> <a href="mailto:aragorn168b@gmail.com">aragorn168b@gmail.com</a><br>Cc: <span style="color:black">Stavros Macrakis (Σταῦρος Μακράκης)</span> <a href="mailto:macrakis@alum.mit.edu">macrakis@alum.mit.edu</a>, <span style="color:black">datatable-help</span> <a href="mailto:datatable-help@r-forge.wu-wien.ac.at">datatable-help@r-forge.wu-wien.ac.at</a><br>Subject: <span style="color:black"> Re: [datatable-help] Speeding up column references with roll <br></span></div><br> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>One other comment. I wonder if .EACHI could mean by each row if there
<br>were no join specified so this:
<br>
<br>library(data.table)
<br>DT <- data.table(
<br> v1 = factor(c("a", "a", "a", "b", "b", "b")),
<br> v2 = c(1, 1, 6, 3, 4, 5),
<br> v3 = c("a", "b", "c", "a", "b", "c"),
<br> stringsAsFactors=FALSE
<br>)
<br>DT[, c(.SD, split(v2, v1)), by = 1:nrow(DT)][, -1, with = FALSE]
<br>
<br>could be written:
<br>
<br>DT[, c(.SD, split(v2, v1)), by = .EACHI]
<br>
<br>or maybe even:
<br>
<br>DT[, split(v2, v1), by = c(names(DT), .EACHI)]
<br>
<br>
<br>On Mon, Jun 30, 2014 at 2:21 PM, Gabor Grothendieck
<br><ggrothendieck@gmail.com> wrote:
<br>> On Mon, Jun 30, 2014 at 1:00 PM, Arunkumar Srinivasan
<br>> <aragorn168b@gmail.com> wrote:
<br>>> Once again, has been fixed in 1.9.3. Now join requires `by=.EACHI`
<br>>> (explicit) to perform a by-without-by.
<br>>> https://github.com/Rdatatable/data.table/blob/master/README.md
<br>>
<br>> The README would be easier to understand if DT was not undefined in
<br>> the README. As it stands none of the examples are runnable.
<br>
<br>
<br>
<br>--
<br>Statistics & Software Consulting
<br>GKX Group, GKX Associates Inc.
<br>tel: 1-877-GKX-GROUP
<br>email: ggrothendieck at gmail.com
<br></div></div></span></blockquote></body></html>