[datatable-help] Top N Items [was: Environment of eval() execution for "j" appears to vary inexplicably]
Matthew Dowle
mdowle at mdowle.plus.com
Mon Jul 5 09:11:51 CEST 2010
Thanks for this example. Interesting. This is grouping of grouping then,
and making it general too. I guess speed is very important as you'd like
to use 'by=' for the subgroups too rather than tapply. I see where
you're coming from now.
This isn't generalised, but this is how I might approach it :
setkey(DT,A) # keep top 3 A by mean(C)
DT$A[-DT[ head(DT[,mean(C),by=A][order(V1,decreasing=TRUE)],3),
which=TRUE, mult="all"]] = NA
setkey(DT,B) # keep top 3 B by mean(C)
DT$B[-DT[ head(DT[,mean(C),by=B][order(V1,decreasing=TRUE)],3),
which=TRUE, mult="all"]] = NA
DT[,mean(C),by=list(A,B)][order(V1,decreasing=TRUE)]
A B V1
[1,] c D 710.4716
[2,] c E 692.5095
[3,] b H 599.4201
[4,] b E 572.1907
[5,] a H 530.2149
[6,] b D 524.7078
[7,] c <NA> 514.0045
[8,] a <NA> 490.4854
[9,] b <NA> 484.2036
[10,] <NA> E 471.2445
[11,] <NA> <NA> 445.4304
It uses NA rather than "(Other)" to avoid building a new factor at the
original DT level, saving time and memory. After you have the aggregate
result you can always replace the NA with '(Other)' to make it pretty.
Notice in your top() the as.character() and the %in% which are things to
avoid if possible, for speed. The code above is doing the same thing
really but using a fast join.
To not change DT, take a copy first, add columns rather than change A or
B, or work on a local variable inside a function.
A trick to get a 'not-join' is to use the 'which' argument, and negative
integer like that. Maybe data.table should have a new 'notjoin' argument
to make that built-in.
Admittedly, this isn't a general interface in the way yours works. Its
not a single query. The only way I can think of right now, to not pass
DT into top() in yours is to use tapply inside top(). That would make it
less complicated, but slower. Maybe you can combine the approaches
somehow. If you time either approach on large data I'd be interested in
the results.
Hope that helps a little,
Matthew
On Fri, 2010-07-02 at 20:11 -0700, Harish wrote:
> Matthew,
>
> My code for top() along with a working example follows.
>
> I had tried to think about a way to avoid passing in the DT, but I couldn't think of a way. I need the data.table because I am creating a few queries on the entire table as you'll see. I suppose if this feature was implemented inside the data.table package, it could be done.
>
> I am still learning how to deal with expressions being passed in and manipulating it without having it being evaluated in my function (since it has to be done by data.table). So, if you find any fundamental flaws in my thinking that is complicating the code, please let me know.
>
> Also, I am new to R coding conventions. So pointers are appreciated.
>
> top <- function( DT, v, criteria, num=10, decreasing=FALSE, unique=FALSE, otherlab="(Other)" ) {
> qcriteria <- parse( text=paste( "list( V = ",
> deparse( substitute( criteria ) ),
> " )" ) )[[ 1 ]]
> qlv <- bquote( list( .( substitute( v ) ) ) )
> qv <- bquote( .( substitute( v ) ) )
>
> nDec <- ifelse( decreasing, -1, 1 )
> dtTop <- DT[ , eval( qcriteria ) ,
> by=eval( qlv )
> ][ order( nDec * V ) ]
> nItems <- min( nrow( dtTop ), num )
> astrTopLevels <- as.character( dtTop[ 1:nItems, eval( qv ) ] )
>
> # Show the top names only
> if ( unique == TRUE )
> return( astrTopLevels )
> # Show the list of newly categorized names for the data
> else
> return( factor(
> ifelse( as.character( DT[[ deparse( substitute( v ) ) ]] ) %in% astrTopLevels,
> as.character( DT[[ deparse( substitute( v ) ) ]] ),
> otherlab ),
> c( astrTopLevels, otherlab )
> )
> )
> }
>
> # Random data being created
> DT <- data.table( A=sample( letters[1:4], 50, replace=TRUE, prob=c(.2, .4, .1, .1) ),
> B=sample( LETTERS[1:8], 50, replace=TRUE, prob=c(.4, .3, .1, .05, .05, .05, .05, .05) ),
> C=rnorm(50, mean=500, sd=150) )
>
> # Get the Top A's and B's.
> DT[ , list( meanC=mean(C) ) , by=list( topA=top( DT, A, mean(C), 3, decreasing=TRUE ), topB=top( DT, B, mean(C), 3, decreasing=TRUE ) ) ]
>
>
> The concept is very similar to Pivot tables in Excel. It has a feature where it can show the Top N items. The top N in this case is computed with the full data.
>
> I am still thinking about a nice way to implement "Top N" items within each category. While I know how to get it done for a one-time-event, I am not sure how to do it nicely as a utility function. A real-life example could be "I want to see top N factories in each state based on its volume of production (along with seeing the Others aggregated)."
>
> Pivot tables in Excel have some other powerful features in it that I want to figure out how to do it "easily" using data.tables using helper functions.
>
> My final goal is to get something similar to pivot tables where the data can be reshaped (similar to cast() in reshape package) as well. Your comments will be highly helpful in pushing me along those lines.
>
>
> Regards,
> Harish
>
>
>
> --- On Fri, 7/2/10, Matthew Dowle <mdowle at mdowle.plus.com> wrote:
>
> > From: Matthew Dowle <mdowle at mdowle.plus.com>
> > Subject: Re: [datatable-help] Environment of eval() execution for "j" appears to vary inexplicably
> > To: "Harish" <harishv_99 at yahoo.com>
> > Cc: datatable-help at lists.r-forge.r-project.org
> > Date: Friday, July 2, 2010, 4:32 PM
> > Actually, can you provide a full
> > reproducible example of that by=top()
> > example with dummy data ?
> >
> > I'm thinking why not use an expression of columns directly
> > in the by?
> >
> > by = list(..,cut(somecol,...),...)
> >
> > or
> >
> > by =
> > list(..,top(top_criteria,sort_order,num_items),...)
> >
> > why does DT have to passed in to top basically ? What are
> > some examples
> > of top_criteria ?
> >
> > Matthew
> >
> >
> > On Fri, 2010-07-02 at 17:33 +0100, mdowle at mdowle.plus.com
> > wrote:
> > > Glad to hear it was that.
> > > Yes dput is similar to dump, great, all sorted.
> > > Your top() is very neat. I had to double-take for a
> > second as it looks
> > > strange to have DT repeated again inside the by, but
> > it reads well now. I
> > > can't think of any better way, looks like you nailed
> > it.
> > > Will look at the crash bug.
> > > Matthew
> > >
> > >
> > > > Thank you Matthew. The issue was the
> > "class" not having "data.frame".
> > > > The bug fix you had made works perfectly.
> > > >
> > > > I had read online to use dput() to recreate
> > variables for posting online.
> > > > This, I understand, is good at times because
> > there could be other aspects
> > > > of the variables (other than the values) that
> > could be contributing to the
> > > > problem. (I did not know about dump()).
> > > >
> > > > Having "(Other)" in the level is a by product of
> > how I found the bug. I
> > > > was trying to create a function "top" which would
> > keep the top N labels
> > > > (where top N is measured in some fashion) and
> > mark the others with
> > > > "(Other)". I had originally used the same
> > function to recreate the
> > > > problem on dummy data and took a dput() dump of
> > the data from somewhere in
> > > > the middle of the processing. This allowed
> > me to have "simpler" functions
> > > > to paste on here to reproduce the problem without
> > much extraneous code.
> > > > That is why you had that the extra level in
> > there.
> > > >
> > > > FYI, my original objective was to use my function
> > top() to group on those
> > > > values; so I would be focusing on the "important"
> > values without being
> > > > overwhelmed with the large amount of
> > "unimportant" data.
> > > > DT[ , list( Col1, Col2),
> > by=top( DT, top_criteria, sort_order,
> > > > num_items_to_show ) ]
> > > > If there is a better way to do the above, please
> > comment.
> > > >
> > > > Thanks a bunch for all your help!
> > > >
> > > >
> > > > Regards,
> > > > Harish
> > > >
> > > >
> > > > --- On Fri, 7/2/10, mdowle at mdowle.plus.com
> > <mdowle at mdowle.plus.com>
> > wrote:
> > > >
> > > >> From: mdowle at mdowle.plus.com
> > <mdowle at mdowle.plus.com>
> > > >> Subject: Re: [datatable-help] Environment of
> > eval() execution for "j"
> > > >> appears to vary inexplicably
> > > >> To: "Harish" <harishv_99 at yahoo.com>
> > > >> Cc: datatable-help at lists.r-forge.r-project.org
> > > >> Date: Friday, July 2, 2010, 2:15 AM
> > > >> Note the class of A is "data.table"
> > > >> in the structure() rather than
> > > >> c("data.table","data.frame").
> > > >>
> > > >> Now whilst, even so, I don't fully understand
> > why the error
> > > >> is occurring,
> > > >> if you could try creating the data.table
> > using data.table()
> > > >> to create the
> > > >> correct structure, rather than structure
> > manually, and see
> > > >> if that fixes
> > > >> it. Since the structure has changed
> > between 1.4.1 and
> > > >> now, thats where
> > > >> the '1.4.1 knocking around' might be coming
> > in.
> > > >>
> > > >> I've noticed use of structure() in other
> > threads and had
> > > >> assumed you were
> > > >> using dump(..,file="") as I think some
> > posting guidlines
> > > >> say. I personally
> > > >> prefer to see the data.table() call to create
> > the dummy
> > > >> data, as I can
> > > >> read it quicker.
> > > >>
> > > >> Also why do return a factor constructed using
> > structure()?
> > > >> If you want
> > > >> extra unused levels (e.g. '(Other)'), then
> > factor() has a
> > > >> levels argument
> > > >> for that purpose.
> > > >>
> > > >> Anyway, might not be that, just first thing
> > to try ..
> > > >>
> > > >>
> > > >> > Unfortunate. I still get the
> > error. I did
> > > >> the following:
> > > >> >
> > > >> > 1) Deleted the "data.table" folder in
> > win-library
> > > >> > 2) Started R with "--vanilla" parameter
> > > >> > 3) Installed the binaries from R-Forge
> > > >> > 4) Restarted R
> > > >> > 5) Ran the test case below
> > > >> >
> > > >> > Would someone else also try the
> > following test
> > > >> case? That would help
> > > >> > isolate whether it is my configuration
> > that is causing
> > > >> the problem.
> > > >> > Thanks.
> > > >> >
> > > >> > ======== Start My R Session ========
> > > >> >
> > > >> >> search()
> > > >> > [1] ".GlobalEnv"
> >
> > > >> "package:data.table"
> > "package:stats"
> > > >> > [4]
> > > >>
> > "package:graphics" "package:grDevices"
> > > >> "package:utils"
> > > >> > [7]
> > > >>
> > "package:datasets" "package:methods"
> > > >> "Autoloads"
> > > >> > [10] "package:base"
> > > >> >> loadedNamespaces()
> > > >> > [1] "base"
> > "data.table"
> > > >> "graphics" "grDevices"
> > "methods"
> > > >> > [6] "stats" "utils"
> > > >> >> sessionInfo()
> > > >> > R version 2.11.1 (2010-05-31)
> > > >> > i386-pc-mingw32
> > > >> >
> > > >> > locale:
> > > >> > [1] LC_COLLATE=English_United
> > States.1252
> > > >> > [2] LC_CTYPE=English_United States.1252
> > > >> > [3] LC_MONETARY=English_United
> > States.1252
> > > >> > [4] LC_NUMERIC=C
> > > >> > [5] LC_TIME=English_United States.1252
> > > >> >
> > > >> > attached base packages:
> > > >> > [1] stats
> > graphics
> > > >> grDevices utils
> > datasets
> > > >> methods base
> > > >> >
> > > >> > other attached packages:
> > > >> > [1] data.table_1.5
> > > >> >>
> > > >> >
> > > >> > ======== End My R Session ========
> > > >> >
> > > >> >
> > > >> > ======== Example code ========
> > > >> >
> > > >> > A <- structure(list(a =
> > structure(1:3, .Label =
> > > >> c("A", "C", "D"), class =
> > > >> > "factor"),
> > > >> > Count = c(4L,
> > 8L, 1L)), .Names
> > > >> = c("a", "Count"), class =
> > > >> > "data.table")
> > > >> >
> > > >> > foo1 <- function(DT) {
> > > >> > dtRet <- DT[ ,
> > > >> >
> > > >> list( Count=sum( Count ) ),
> > > >> >
> > > >> by=list( Category=foo2( DT, a )
> > )
> > > >> > ]
> > > >> > invisible()
> > > >> > }
> > > >> >
> > > >> >
> > > >> > foo2 <- function( DT, v ) {
> > > >> > q <- substitute( v )
> > > >> >
> > > >> > print( identical( q,
> > substitute( v ) )
> > > >> ) # TRUE as expected
> > > >> > print( DT[ 1:2, eval( q ) ]
> > )
> > > >> > print( DT[ 1:2, eval(
> > substitute( v ) ) ]
> > > >> )
> > > >> > return( structure(1:3,
> > .Label = c("A",
> > > >> "C", "D", "(Other)"), class =
> > > >> > "factor") )
> > > >> > }
> > > >> >
> > > >> > foo1( A ) # Test 1
> > > >> > foo2( A, a ) # Test 2
> > > >> > === End code ===
> > > >> >
> > > >> > I get the following output:
> > > >> >
> > > >> >> foo1( A ) # Test 1
> > > >> > [1] TRUE
> > > >> > [1] A C
> > > >> > Levels: A C D
> > > >> > [1] A C
> > > >> > Levels: A C D
> > > >> > Error: evaluation nested too deeply:
> > infinite
> > > >> recursion /
> > > >> > options(expressions=)?
> > > >> >> foo2( A, a ) # Test 2
> > > >> > [1] TRUE
> > > >> > [1] A C
> > > >> > Levels: A C D
> > > >> > [1] A C
> > > >> > Levels: A C D
> > > >> > [1] A C D
> > > >> > Levels: A C D (Other)
> > > >> >>
> > > >> >
> > > >> > Note the error in the middle...
> > > >> >
> > > >> >
> > > >> > Harish
> > > >> >
> > > >> > --- On Thu, 7/1/10, mdowle at mdowle.plus.com
> > > >> <mdowle at mdowle.plus.com>
> > > >> wrote:
> > > >> >
> > > >> >> From: mdowle at mdowle.plus.com
> > > >> <mdowle at mdowle.plus.com>
> > > >> >> Subject: Re: [datatable-help]
> > Environment of
> > > >> eval() execution for "j"
> > > >> >> appears to vary inexplicably
> > > >> >> To: "Harish" <harishv_99 at yahoo.com>
> > > >> >> Cc: datatable-help at lists.r-forge.r-project.org
> > > >> >> Date: Thursday, July 1, 2010, 2:01
> > AM
> > > >> >>
> > > >> >> I've seen that before. For me it was
> > because
> > > >> version 1.4.1
> > > >> >> of data.table
> > > >> >> was still knocking around. For
> > me I looked at
> > > >> >> loadedNamespaces() and it
> > > >> >> listed data.table, but search() did
> > not.
> > > >> >>
> > > >> >> The loop happens because of the
> > particular changes
> > > >> that
> > > >> >> have happened
> > > >> >> between 1.4.1 and latest 1.5, AND
> > having both
> > > >> versions
> > > >> >> somehow visible to
> > > >> >> R at the same time, in some way
> > conflicting with
> > > >> each
> > > >> >> other. Or at least
> > > >> >> thats what it was for me.
> > > >> >>
> > > >> >> To be sure, start R with --vanilla,
> > for me on
> > > >> ubuntu I have
> > > >> >> to "sudo R
> > > >> >> --vanilla" anyway because of
> > permissions (which I
> > > >> like).
> > > >> >>
> > > >> >> Then install.packages(...) to
> > cleanly install.
> > > >> Then restart
> > > >> >> R. The error
> > > >> >> should go away?
> > > >> >>
> > > >> >>
> > > >> >> > Matthew,
> > > >> >> >
> > > >> >> > Thanks for the fix. It
> > almost works... I
> > > >> >> tested it on Rev 101 binaries.
> > > >> >> >
> > > >> >> > I get an extra line of output
> > for the test
> > > >> case #1 I
> > > >> >> mentioned...
> > > >> >> >
> > > >> >> >> foo1( A ) # Test 1
> > > >> >> > [1] TRUE
> > > >> >> > [1] A C
> > > >> >> > Levels: A C D
> > > >> >> > [1] A C
> > > >> >> > Levels: A C D
> > > >> >> > Error: evaluation nested too
> > deeply:
> > > >> infinite
> > > >> >> recursion /
> > > >> >> > options(expressions=)?
> > > >> >> >>
> > > >> >> >
> > > >> >> > Please note that I get an error
> > at the
> > > >> end.
> > > >> >> Though, the output seems to
> > > >> >> > be right.
> > > >> >> >
> > > >> >> >
> > > >> >> > Regards,
> > > >> >> > Harish
> > > >> >> >
> > > >> >> >
> > > >> >> > --- On Tue, 6/29/10, Matthew
> > Dowle <mdowle at mdowle.plus.com>
> > > >> >> wrote:
> > > >> >> >
> > > >> >> >> From: Matthew Dowle <mdowle at mdowle.plus.com>
> > > >> >> >> Subject: Re:
> > [datatable-help] Environment
> > > >> of
> > > >> >> eval() execution for "j"
> > > >> >> >> appears to vary
> > inexplicably
> > > >> >> >> To: "Harish" <harishv_99 at yahoo.com>
> > > >> >> >> Cc: datatable-help at lists.r-forge.r-project.org
> > > >> >> >> Date: Tuesday, June 29,
> > 2010, 1:43 PM
> > > >> >> >> Yes, that was reproducible,
> > thanks.
> > > >> >> >>
> > > >> >> >> The last commit 101 fixes
> > this one too, I
> > > >> think.
> > > >> >> Please
> > > >> >> >> confirm.
> > > >> >> >>
> > > >> >> >> A =
> > data.table(a=c("A","C","D"),
> > > >> >> Count=c(4L,8L,1L))
> > > >> >> >>
> > > >> >> >> > foo1(A)
> > > >> >> >> [1] TRUE
> > > >> >> >> [1] A C
> > > >> >> >> Levels: A C D
> > > >> >> >> [1] A C
> > > >> >> >> Levels: A C D
> > > >> >> >>
> > > >> >> >> > foo2(A,a)
> > > >> >> >> [1] TRUE
> > > >> >> >> [1] A C
> > > >> >> >> Levels: A C D
> > > >> >> >> [1] A C
> > > >> >> >> Levels: A C D
> > > >> >> >> [1] A C D
> > > >> >> >> Levels: A C D (Other)
> > > >> >> >> >
> > > >> >> >>
> > > >> >> >> Matthew
> > > >> >> >>
> > > >> >> >>
> > > >> >> >> On Sat, 2010-06-26 at 00:28
> > -0700, Harish
> > > >> wrote:
> > > >> >> >> > I am running into a
> > peculiar issue
> > > >> which
> > > >> >> seems to be
> > > >> >> >> related to the environment
> > in which the
> > > >> eval() is
> > > >> >> executed
> > > >> >> >> when passed as the
> > "j". The environment
> > > >> of
> > > >> >> execution
> > > >> >> >> of the eval() seems to vary
> > depending on
> > > >> whether I
> > > >> >> pass in a
> > > >> >> >> variable (of class "name")
> > or an
> > > >> equivalent
> > > >> >> expression is
> > > >> >> >> typed inside the eval.
> > > >> >> >> >
> > > >> >> >> > === Example code ===
> > > >> >> >> >
> > > >> >> >> > A <-
> > structure(list(a =
> > > >> structure(1:3,
> > > >> >> .Label =
> > > >> >> >> c("A", "C", "D"), class =
> > "factor"),
> > > >> >> >> >
> > Count = c(4L, 8L, 1L)),
> > > >> .Names
> > > >> >> >> = c("a", "Count"), class =
> > "data.table")
> > > >> >> >> >
> > > >> >> >> > foo1 <-
> > function(DT) {
> > > >> >> >> > dtRet
> > <- DT[ ,
> > > >> >> >> >
> >
> > > >> >> >> list(
> > Count=sum( Count ) ),
> > > >> >> >> >
> >
> > > >> >> >> by=list(
> > Category=foo2( DT, a ) )
> > > >> >> >> >
> > ]
> > > >> >> >> >
> > invisible()
> > > >> >> >> > }
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> > foo2 <- function(
> > DT, v ) {
> > > >> >> >> > q <-
> > substitute( v )
> > > >> >> >> >
> > > >> >> >> > print(
> > identical( q,
> > > >> substitute( v ) )
> > > >> >> >> ) # TRUE
> > as expected
> > > >> >> >> > print(
> > DT[ 1:2, eval( q ) ] )
> > > >> >> >> > print(
> > DT[ 1:2, eval(
> > > >> substitute( v ) )
> > > >> >> ]
> > > >> >> >> )
> > > >> >> >> > return(
> > structure(1:3, .Label =
> > > >> c("A",
> > > >> >> >> "C", "D", "(Other)"), class
> > = "factor")
> > > >> )
> > > >> >> >> > }
> > > >> >> >> >
> > > >> >> >> > foo1( A ) # Test 1
> > > >> >> >> > foo2( A, a ) # Test 2
> > > >> >> >> > === End code ===
> > > >> >> >> >
> > > >> >> >> > In Test 1, when I run
> > foo1(), I am
> > > >> >> essentially
> > > >> >> >> executing
> > > >> >> >> > foo2( A,
> > a ) from within the
> > > >> code of
> > > >> >> the
> > > >> >> >> data table.
> > > >> >> >> >
> > > >> >> >> > I get:
> > > >> >> >> > [1] TRUE
> > > >> >> >> > [1] A C
> > > >> >> >> > Levels: A C D
> > > >> >> >> > [1] A C D
> > > >> >> >> > Levels: A C D
> > > >> >> >> >
> > > >> >> >> > Issue #1 ==> The
> > third print in
> > > >> foo2() is
> > > >> >> actually
> > > >> >> >> returning 3 items when I am
> > requesting
> > > >> only the
> > > >> >> first 2
> > > >> >> >> items. (Also, in my
> > more complex
> > > >> program, it
> > > >> >> seemed to
> > > >> >> >> return the data in
> > alphabetical order or
> > > >> the order
> > > >> >> of the
> > > >> >> >> factor levels rather than
> > in the order of
> > > >> the data
> > > >> >> in the
> > > >> >> >> table. However, I am
> > not able to
> > > >> reproduce this
> > > >> >> in a
> > > >> >> >> simpler example. I am
> > hoping that this
> > > >> behavior
> > > >> >> will
> > > >> >> >> also be rectified with any
> > bug fixes you
> > > >> make.)
> > > >> >> >> >
> > > >> >> >> > In Test 2, I run
> > foo2() directly in
> > > >> >> .GlobalEnv, but I
> > > >> >> >> am passing in the same data
> > that foo1()
> > > >> would have
> > > >> >> passed it
> > > >> >> >> in Test 1.
> > > >> >> >> >
> > > >> >> >> > I get:
> > > >> >> >> > [1] TRUE
> > > >> >> >> > [1] A C
> > > >> >> >> > Levels: A C D
> > > >> >> >> > Error in eval(expr,
> > envir, enclos) :
> > > >> object
> > > >> >> 'a' not
> > > >> >> >> found
> > > >> >> >> >
> > > >> >> >> > Issue #2 ==> It
> > looks like if I
> > > >> have an
> > > >> >> expression
> > > >> >> >> inside eval(), it is
> > executed in a
> > > >> different
> > > >> >> environment as
> > > >> >> >> the prior print statement
> > where I have an
> > > >> eval()
> > > >> >> with just a
> > > >> >> >> single variable.
> > Technically, I would
> > > >> expect
> > > >> >> both to
> > > >> >> >> be equivalent.
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> > I hope I clearly
> > explained what my
> > > >> issues
> > > >> >> are.
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> > Regards,
> > > >> >> >> > Harish
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> >
> > > >> >> >> >
> >
> > > >> >> >> >
> > > >> >>
> > _______________________________________________
> > > >> >> >> > datatable-help mailing
> > list
> > > >> >> >> > datatable-help at lists.r-forge.r-project.org
> > > >> >> >> > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
> > > >> >> >>
> > > >> >> >>
> > > >> >> >>
> > > >> >> >
> > > >> >> >
> > > >> >> >
> > > >> >> >
> > > >> >>
> > > >> >>
> > > >> >>
> > > >> >
> > > >> >
> > > >> >
> > > >> >
> > > >>
> > > >>
> > > >>
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > _______________________________________________
> > > datatable-help mailing list
> > > datatable-help at lists.r-forge.r-project.org
> > > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/datatable-help
> >
> >
> >
>
>
>
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