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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div class="bloop_markdown"><p>GSee and List,</p>
<p>With <a href="https://github.com/Rdatatable/data.table/commit/e0ce69a2c22c9573cba71c4c6aca108bc08e697c">commit 1336</a>, this now works:</p>
<pre><code class="R">require(data.table)
L = list(as.data.table(BOD), as.data.table(BOD))
lapply(L, "[", Time == 3L)
</code></pre>
<p>Please write back if you come across any issues.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><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_1407110086777780992" 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">G See</span> <a href="mailto:gsee000@gmail.com"><gsee000@gmail.com></a><br>Reply: <span style="color:black">G See</span> <a href="mailto:gsee000@gmail.com"><gsee000@gmail.com>></a><br>Date: <span style="color:black">November 11, 2013 at 3:40:46 PM</span><br>To: <span style="color:black">Gabor Grothendieck</span> <a href="mailto:ggrothendieck@gmail.com"><ggrothendieck@gmail.com>></a><br>Cc: <span style="color:black">datatable-help@lists.r-forge.r-project.org</span> <a href="mailto:datatable-help@lists.r-forge.r-project.org"><datatable-help@lists.r-forge.r-project.org>></a><br>Subject: <span style="color:black"> Re: [datatable-help] lapply without anonymous function <br></span></div><br> <blockquote type="cite" class="clean_bq"><span><div><div>heh, after all my efforts to avoid subset(), it can be useful after all. :)
<br>
<br>Bug report filed, per Eduard's suggestion.
<br>
<br>On Mon, Nov 11, 2013 at 8:06 AM, Gabor Grothendieck
<br><ggrothendieck@gmail.com> wrote:
<br>> On Sun, Nov 10, 2013 at 2:39 PM, G See <gsee000@gmail.com> wrote:
<br>>> Hi,
<br>>>
<br>>> I have a list of data.tables and I am trying to extract a subset from
<br>>> each of them. I can achieve what I want with this:
<br>>>
<br>>>> L <- list(data.table(BOD), data.table(BOD))
<br>>>> lapply(L, function(x) x[Time==3L])
<br>>> [[1]]
<br>>> Time demand
<br>>> 1: 3 19
<br>>>
<br>>> [[2]]
<br>>> Time demand
<br>>> 1: 3 19
<br>>>
<br>>> However, I'd rather not type have to create an anonymous function. I
<br>>> tried the below, but `[.data.frame` is being dispatched.
<br>>>
<br>>>> lapply(L, "[", Time==3L)
<br>>> Error in `[.data.frame`(x, i) : object 'Time' not found
<br>>>
<br>>> Even if I am explicit, `[.data.table` does not get dispatched:
<br>>>
<br>>>> lapply(L, data.table:::`[.data.table`, Time==3L)
<br>>> Error in `[.data.frame`(x, i) : object 'Time' not found
<br>>>
<br>>> I'm guessing this is due to where evaluation takes place. Is there an
<br>>> alternate syntax I should use?
<br>>>
<br>>
<br>> subset works:
<br>>
<br>>> lapply(L, subset, Time == 3L)
<br>> [[1]]
<br>> Time demand
<br>> 1: 3 19
<br>>
<br>> [[2]]
<br>> Time demand
<br>> 1: 3 19
<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
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