Re: [R] data.frame with a column containing an array
Maybe a better solution instead of "don't do it!" might be to change:
x[[j]] <- if(length(dim(xj)) != 2L) xj[i] else xj[i, , drop = FALSE]
at:
https://github.com/wch/r-source/blob/trunk/src/library/base/R/dataframe.R#L712
to:
x[[j]] <- if(length(dim(xj)) < 2L) xj[i] else do.call("[",c(list(xj,i),
rep(list(bquote()), length(dim(xj))-1L), list(drop = FALSE)))
Would this be possible and work?
Thanks!
Georg
Gesendet: Freitag, 26. Mai 2023 um 21:05 Uhr
Von: "Bert Gunter"
An: "Georg Kindermann"
Cc: "Rui Barradas" , r-help@r-project.org, "Jeff
Newmiller"
Betreff: Re: Re: Re: [R] data.frame with a column containing an array
Please refer to Jeff Newmiller's response. I believe that your further
exploration of indexing a data frame containing an array column
demonstrates his point: don't do it!
As this discussion could now devolve into a morass of personal opinion
(such as the above), if you or others care to continue, please do so
**offlist**. However, I have nothing further to say in any case.
Cheers,
Bert
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Re: [R] data.frame with a column containing an array
Dear Bert! Thanks for the answer. Just let me summarize the current (4.3.0) behavior. DF <- data.frame(id = 1:2) DF[["ar"]] <- array(1:8, c(2,2,2)) #Converts array to vector #Removes dim and takes selected elements from first column DF[1,] # id ar #1 1 1 str(DF[1,]) #'data.frame': 1 obs. of 2 variables: # $ id: int 1 # $ ar: int 1 #Converts array to vector #Removes dim and takes selected elements DF[c(TRUE, FALSE),] # id ar #1 1 1 #Warning message: #In format.data.frame(if (omit) x[seq_len(n0), , drop = FALSE] else x, : # corrupt data frame: columns will be truncated or padded with NAs str(DF[c(TRUE, FALSE),]) #'data.frame': 1 obs. of 2 variables: # $ id: int 1 # $ ar: int 1 3 5 7 #Converts array to vector #Removes dim and takes selected elements from first column and #adds all elements form the remaining data DF[-2,] # id ar #1 1 1 #Warning message: #In format.data.frame(if (omit) x[seq_len(n0), , drop = FALSE] else x, : # corrupt data frame: columns will be truncated or padded with NAs str(DF[-2,]) #'data.frame': 1 obs. of 2 variables: # $ id: int 1 # $ ar: int 1 3 4 5 6 7 8 #Converts array to vector #Removes dim but keeps all elements DF[TRUE,] # id ar #1 1 1 #2 2 2 #Warning message: #In format.data.frame(if (omit) x[seq_len(n0), , drop = FALSE] else x, : # corrupt data frame: columns will be truncated or padded with NAs str(DF[TRUE,]) #'data.frame': 2 obs. of 2 variables: # $ id: int 1 2 # $ ar: int 1 2 3 4 5 6 7 8 Kind regards, Georg Gesendet: Donnerstag, 25. Mai 2023 um 19:15 Uhr Von: "Bert Gunter" An: "Georg Kindermann" Cc: "Rui Barradas" , r-help@r-project.org Betreff: Re: Re: [R] data.frame with a column containing an array I really don't know. I would call it a request for extended capabilities of [.data.frame, rather than a feature or bug. But maybe wiser heads than mine who monitor this list can sort it out. -- Bert __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] data.frame with a column containing an array
So is this an expected behavior or is it a bug which should be reported somewhere else? Thanks! Georg Gesendet: Dienstag, 09. Mai 2023 um 19:28 Uhr Von: "Bert Gunter" An: "Georg Kindermann" Cc: "Rui Barradas" , r-help@r-project.org Betreff: Re: [R] data.frame with a column containing an array I think the following may provide a clearer explanation: subs <- c(1,3) DFA <- data.frame(id = 1:3) ar <- array(1:12, c(3,2,2)) ## yielding > ar , , 1 [,1] [,2] [1,] 1 4 [2,] 2 5 [3,] 3 6 , , 2 [,1] [,2] [1,] 7 10 [2,] 8 11 [3,] 9 12 ## array subscripting gives > ar[subs,,] , , 1 [,1] [,2] [1,] 1 4 [2,] 3 6 , , 2 [,1] [,2] [1,] 7 10 [2,] 9 12 ## Now with df's > DFA[["ar"]] <- ar > > DFM <- data.frame(id = 1:3) > DFM[["M"]] <- matrix(1:6, nc =2) > > str(DFM) 'data.frame': 3 obs. of 2 variables: $ id: int 1 2 3 $ M : int [1:3, 1:2] 1 2 3 4 5 6 > str(DFA) 'data.frame': 3 obs. of 2 variables: $ id: int 1 2 3 $ ar: int [1:3, 1:2, 1:2] 1 2 3 4 5 6 7 8 9 10 ... > > ## But the data frame print method for these give > DFM id M.1 M.2 1 1 1 4 2 2 2 5 3 3 3 6 > DFA id ar.1 ar.2 ar.3 ar.4 1 1 1 4 7 10 2 2 2 5 8 11 3 3 3 6 9 12 > > ## [.data.frame subscripting gives > DFA[subs,] id ar 1 1 1 3 3 3 > DFM[subs,] id M.1 M.2 1 1 1 4 3 3 3 6 > > ## but explicit array subscripting of course works > DFA$ar[match(subs,DFA$id),,] , , 1 [,1] [,2] [1,] 1 4 [2,] 3 6 , , 2 [,1] [,2] [1,] 7 10 [2,] 9 12 Cheers, Bert __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] data.frame with a column containing an array
Thanks! With data.table I'm not able to create it. DT <- data.table::data.table(id = 1:2) DT$ar <- array(1:8, c(2,2,2)) #Error in set(x, j = name, value = value) : # Supplied 8 items to be assigned to 2 items of column 'ar'. If you wish to 'recycle' the RHS please use rep() to make this intent clear to readers of your code. DFA <- data.frame(id = 1:2) DFA[["ar"]] <- array(1:8, c(2,2,2)) data.table::as.data.table(DFA) #Error in setDT(ans, key = key) : # All elements in argument 'x' to 'setDT' must be of same length, but the profile of input lengths (length:frequency) is: [0:1, 2:2] #The first entry with fewer than 2 entries is 3 But with tibble it works as expected. TI <- tibble::tibble(id = 1:2, ar = array(1:8, c(2,2,2))) str(TI[1,]) #tibble [1 × 2] (S3: tbl_df/tbl/data.frame) # $ id: int 1 # $ ar: int [1, 1:2, 1:2] 1 3 5 7 But it would be nice if something similar would also work with data.frame. Georg Gesendet: Dienstag, 09. Mai 2023 um 16:56 Uhr Von: "Bert Gunter" An: "Georg Kindermann" Cc: "Rui Barradas" , r-help@r-project.org Betreff: Re: [R] data.frame with a column containing an array Right ... that's what I thought you meant. I'm pretty sure -- but not certain -- that columns of matrices are treated specially by [.data.frame, so that you have to explicitly index a higher dimensional array, e.g. like this: subs <- c(1,3) DFA <- data.frame(id = 1:3) DFA[["ar"]] <- array(1:12, c(3,2,2)) DFA$ar[match(subs,DFA$id),,] ##yielding: , , 1 [,1] [,2] [1,] 1 4 [2,] 3 6 , , 2 [,1] [,2] [1,] 7 10 [2,] 9 12 You might check, e.g. the "data.table" package, to see if it indexes as you would like with columns that contain arrays. Alternatively, and perhaps preferably depending on your use case, you may wish to create a wholly different data structure or just treat the data frame as a list from the start. Data frames/matrix-like data structures are convenient and appropriate a lot of the time, but not always. R, like any flexible programming language, allows you -- even encourages you -- to create other data structures that fit your needs. Cheers, Bert __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] data.frame with a column containing an array
Thanks! No, to be consistent with what I get with a matrix I think it should be like: x <- data.frame(id = DFA$id[1]) x$ar <- DFA$ar[1, , , drop = FALSE] str(x) #'data.frame': 1 obs. of 2 variables: # $ id: int 1 # $ ar: int [1, 1:2, 1:2] 1 3 5 7 Georg Gesendet: Dienstag, 09. Mai 2023 um 09:32 Uhr Von: "Rui Barradas" An: "Georg Kindermann" , r-help@r-project.org Betreff: Re: [R] data.frame with a column containing an array Às 11:52 de 08/05/2023, Georg Kindermann escreveu: > Dear list members, > > when I create a data.frame containing an array I had expected, that I get a > similar result, when subsetting it, like having a matrix in a data.frame. But > instead I get only the first element and not all values of the remaining > dimensions. Differences are already when creating the data.frame, where I can > use `I` in case of a matrix but for an array I am only able to insert it in a > second step. > > DFA <- data.frame(id = 1:2) > DFA[["ar"]] <- array(1:8, c(2,2,2)) > > DFA[1,] > # id ar > #1 1 1 > > DFM <- data.frame(id = 1:2, M = I(matrix(1:4, 2))) > > DFM[1,] > # id M.1 M.2 > #1 1 1 3 > > The same when trying to use merge, where only the first value is kept. > > merge(DFA, data.frame(id = 1)) > # id ar > #1 1 1 > > merge(DFM, data.frame(id = 1)) > # id M.1 M.2 > #1 1 1 3 > > Is there a way to use an array in a data.frame like I can use a matrix in a > data.frame? > > I am using R version 4.3.0. > > Kind regards, > Georg > > __ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html[http://www.R-project.org/posting-guide.html] > and provide commented, minimal, self-contained, reproducible code. Hello, Are you looking for something like this? DFA <- data.frame(id = 1:2) DFA[["ar"]] <- array(1:8, c(2,2,2)) DFA$ar[1, , ] #> [,1] [,2] #> [1,] 1 5 #> [2,] 3 7 Hope this helps, Rui Barradas __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] data.frame with a column containing an array
Dear list members, when I create a data.frame containing an array I had expected, that I get a similar result, when subsetting it, like having a matrix in a data.frame. But instead I get only the first element and not all values of the remaining dimensions. Differences are already when creating the data.frame, where I can use `I` in case of a matrix but for an array I am only able to insert it in a second step. DFA <- data.frame(id = 1:2) DFA[["ar"]] <- array(1:8, c(2,2,2)) DFA[1,] # id ar #1 1 1 DFM <- data.frame(id = 1:2, M = I(matrix(1:4, 2))) DFM[1,] # id M.1 M.2 #1 1 1 3 The same when trying to use merge, where only the first value is kept. merge(DFA, data.frame(id = 1)) # id ar #1 1 1 merge(DFM, data.frame(id = 1)) # id M.1 M.2 #1 1 1 3 Is there a way to use an array in a data.frame like I can use a matrix in a data.frame? I am using R version 4.3.0. Kind regards, Georg __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
[R] Why is R making a copy-on-modification after using str?
Dear list members, I was wondering why R is making a copy-on-modification after using str. m <- matrix(1:12, 3) tracemem(m) #[1] "<0x559df861af28>" dim(m) <- 4:3 m[1,1] <- 0L m[] <- 12:1 str(m) # int [1:4, 1:3] 12 11 10 9 8 7 6 5 4 3 ... dim(m) <- 3:4 #Here after str a copy is made #tracemem[0x559df861af28 -> 0x559df838e4a8]: dim(m) <- 3:4 str(m) # int [1:3, 1:4] 12 11 10 9 8 7 6 5 4 3 ... dim(m) <- 3:4 #Here again after str a copy #tracemem[0x559df838e4a8 -> 0x559df82c9d78]: Also I was wondering why a copy is made when having a Task Callback. TCB <- addTaskCallback(function(...) TRUE) m <- matrix(1:12, nrow = 3) tracemem(m) #[1] "<0x559dfa79def8>" dim(m) <- 4:3 #Copy on modification #tracemem[0x559dfa79def8 -> 0x559dfa8998e8]: removeTaskCallback(TCB) #[1] TRUE dim(m) <- 4:3 #No copy I am using R version 4.0.3. Kind regards, Georg __ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
