[Rd] as.data.frame.table() does not recognize default.stringsAsFactors()

[peter dalgaard]

I have no recollection of the original rationale for as.data.frame.table, but I actually think it is fine as it is: 

The classifying _factors_ of a crosstable should be factors unless very specifically directed otherwise and that should not depend on the setting of an option that controls the conversion of character data. 

For as.data.frame.matrix, in contrast, it is the _content_ of the matrix that is being converted, and it seems much more reasonable to follow the same path as for other character data.

-pd

> On 12 Mar 2019, at 21:39 , Mychaleckyj, Josyf C (jcm6t) <jcm6t using virginia.edu> wrote:
> 
> Reporting a possible inconsistency or bug in handling stringsAsFactors in as.data.frame.table()
> 
> Here is a simple test
> 
>> options()$stringsAsFactors
> [1] TRUE
>> x<-c("a","b","c","a","b")
>> d<-as.data.frame(table(x))
>> d
>  x Freq
> 1 a    2
> 2 b    2
> 3 c    1
>> class(d$x)
> [1] "factor"
>> d2<-as.data.frame(table(x),stringsAsFactors=F)
>> class(d2$x)
> [1] “character"
>> options(stringsAsFactors=F)
>> options()$stringsAsFactors
> [1] FALSE
>> d3<-as.data.frame(table(x))
>> d3
>  x Freq
> 1 a    2
> 2 b    2
> 3 c    1
>> class(d3$x)
> [1] “factor"
>> d4<-as.data.frame(table(x),stringsAsFactors=F)
>> class(d4$x)
> [1] “character"
> 
> 
> # Display the code showing the different  stringsAsFactors handling in table and matrix:
> 
>> as.data.frame.table
> function (x, row.names = NULL, ..., responseName = "Freq", stringsAsFactors = TRUE,
>    sep = "", base = list(LETTERS))
> {
>    ex <- quote(data.frame(do.call("expand.grid", c(dimnames(provideDimnames(x,
>        sep = sep, base = base)), KEEP.OUT.ATTRS = FALSE, stringsAsFactors = stringsAsFactors)),
>        Freq = c(x), row.names = row.names))
>    names(ex)[3L] <- responseName
>    eval(ex)
> }
> <bytecode: 0x28769f8>
> <environment: namespace:base>
> 
>> as.data.frame.matrix
> function (x, row.names = NULL, optional = FALSE, make.names = TRUE,
>    ..., stringsAsFactors = default.stringsAsFactors())
> {
>    d <- dim(x)
>    nrows <- d[[1L]]
>    ncols <- d[[2L]]
>    ic <- seq_len(ncols)
>    dn <- dimnames(x)
>    if (is.null(row.names))
>        row.names <- dn[[1L]]
>    collabs <- dn[[2L]]
>    if (any(empty <- !nzchar(collabs)))
>        collabs[empty] <- paste0("V", ic)[empty]
>    value <- vector("list", ncols)
>    if (mode(x) == "character" && stringsAsFactors) {
>        for (i in ic) value[[i]] <- as.factor(x[, i])
>    }
>    else {
>        for (i in ic) value[[i]] <- as.vector(x[, i])
>    }
>    autoRN <- (is.null(row.names) || length(row.names) != nrows)
>    if (length(collabs) == ncols)
>        names(value) <- collabs
>    else if (!optional)
>        names(value) <- paste0("V", ic)
>    class(value) <- "data.frame"
>    if (autoRN)
>        attr(value, "row.names") <- .set_row_names(nrows)
>    else .rowNamesDF(value, make.names = make.names) <- row.names
>    value
> }
> <bytecode: 0x29995c0>
> <environment: namespace:base>
> 
> 
>> sessionInfo()
> R version 3.5.2 (2018-12-20)
> Platform: x86_64-pc-linux-gnu (64-bit)
> Running under: CentOS Linux 7 (Core)
> 
> Matrix products: default
> BLAS: /usr/lib64/libblas.so.3.4.2
> LAPACK: /usr/lib64/liblapack.so.3.4.2
> 
> locale:
> [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
> [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
> [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
> [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
> [9] LC_ADDRESS=C               LC_TELEPHONE=C
> [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C
> 
> attached base packages:
> [1] stats     graphics  grDevices utils     datasets  methods   base
> 
> loaded via a namespace (and not attached):
> [1] compiler_3.5.2 tools_3.5.2
> 
> Thanks,
> Joe
> 
> 
> 
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> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
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