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Gabor Grothendieck

2018-Jul-23 14:51 UTC

[Rd] oddity in transform

Note the inconsistency in the names in these two examples.  X.Time in
the first case and Time.1 in the second case.

  > transform(BOD, X = BOD[1:2] * seq(6))
    Time demand X.Time X.demand
  1    1    8.3      1      8.3
  2    2   10.3      4     20.6
  3    3   19.0      9     57.0
  4    4   16.0     16     64.0
  5    5   15.6     25     78.0
  6    7   19.8     42    118.8

  > transform(BOD, X = BOD[1] * seq(6))
    Time demand Time.1
  1    1    8.3      1
  2    2   10.3      4
  3    3   19.0      9
  4    4   16.0     16
  5    5   15.6     25
  6    7   19.8     42

-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

Emil Bode

2018-Jul-24 11:14 UTC

head link

[Rd] oddity in transform

I think you meant to call BOD[,1]
From ?transform, the ... arguments are supposed to be vectors, and BOD[1] is
still a data.frame (with one column). So I don't think it's surprising
transform gets confused by which name to use (X, or Time?), and kind of
compromises on the name "Time". It's also in a note in ?transform:
"If some of the values are not vectors of the appropriate length, you
deserve whatever you get!"
And if you want to do it with multiple extra columns (and are not satisfied with
these labels), I think the proper way to go would be " transform(BOD,
X=BOD[,1]*seq(6), Y=BOD[,2]*seq(6))"

If you want to trace it back further, it's not in transform but in
data.frame. Column-names are prepended with a higher-level name if the object
has more than one column.
And it uses the tag-name if simply supplied with a vector:
data.frame(BOD[1:2], X=BOD[1]*seq(6)) takes the name of the only column of
BOD[1], Time. Only because that column name is already present, it's changed
to Time.1
data.frame(BOD[1:2], X=BOD[,1]*seq(6)) gives third column-name X (as X is now a
vector)
data.frame(BOD[1:2], X=BOD[1:2]*seq(6)) or with BOD[,1:2] gives columns names
X.Time and X.demand, to show these (multiple) columns are coming from X

So I don't think there's much to fix here. I this case having X.Time in
all cases would have been better, but in general the column-naming of data.frame
works, changing it would likely cause a lot of problems.
You can always change the column-names later.

Best regards, 
Emil Bode

Data-analyst

+31 6 43 83 89 33
emil.bode at dans.knaw.nl

DANS: Netherlands Institute for Permanent Access to Digital Research Resources
Anna van Saksenlaan 51 | 2593 HW Den Haag | +31 70 349 44 50 | info at
dans.knaw.nl <mailto:info at dans.kn> | dans.knaw.nl
<applewebdata://71F677F0-6872-45F3-A6C4-4972BF87185B/www.dans.knaw.nl>
DANS is an institute of the Dutch Academy KNAW <http://knaw.nl/nl> and
funding organisation NWO <http://www.nwo.nl/>.

?On 23/07/2018, 16:52, "R-devel on behalf of Gabor Grothendieck"
<r-devel-bounces at r-project.org on behalf of ggrothendieck at gmail.com>
wrote:

    Note the inconsistency in the names in these two examples.  X.Time in
    the first case and Time.1 in the second case.

      > transform(BOD, X = BOD[1:2] * seq(6))
        Time demand X.Time X.demand
      1    1    8.3      1      8.3
      2    2   10.3      4     20.6
      3    3   19.0      9     57.0
      4    4   16.0     16     64.0
      5    5   15.6     25     78.0
      6    7   19.8     42    118.8

      > transform(BOD, X = BOD[1] * seq(6))
        Time demand Time.1
      1    1    8.3      1
      2    2   10.3      4
      3    3   19.0      9
      4    4   16.0     16
      5    5   15.6     25
      6    7   19.8     42

    -- 
    Statistics & Software Consulting
    GKX Group, GKX Associates Inc.
    tel: 1-877-GKX-GROUP
    email: ggrothendieck at gmail.com

    ______________________________________________
    R-devel at r-project.org mailing list
    https://stat.ethz.ch/mailman/listinfo/r-devel

Gabor Grothendieck

2018-Jul-24 11:59 UTC

head link

[Rd] oddity in transform

The idea is that one wants to write the line of code below
 in a general way which works the same
whether you specify ix as one column or multiple columns but the naming entirely
changes when you do this and BOD[, 1] and transform(BOD, X=..., Y=...) or
other hard coding solutions still require writing multiple cases.

ix <- 1:2
transform(BOD, X = BOD[ix] * seq(6))



On Tue, Jul 24, 2018 at 7:14 AM, Emil Bode <emil.bode at dans.knaw.nl>
wrote:> I think you meant to call BOD[,1]
> From ?transform, the ... arguments are supposed to be vectors, and BOD[1]
is still a data.frame (with one column). So I don't think it's
surprising transform gets confused by which name to use (X, or Time?), and kind
of compromises on the name "Time". It's also in a note in
?transform: "If some of the values are not vectors of the appropriate
length, you deserve whatever you get!"
> And if you want to do it with multiple extra columns (and are not satisfied
with these labels), I think the proper way to go would be " transform(BOD,
X=BOD[,1]*seq(6), Y=BOD[,2]*seq(6))"
>
> If you want to trace it back further, it's not in transform but in
data.frame. Column-names are prepended with a higher-level name if the object
has more than one column.
> And it uses the tag-name if simply supplied with a vector:
> data.frame(BOD[1:2], X=BOD[1]*seq(6)) takes the name of the only column of
BOD[1], Time. Only because that column name is already present, it's changed
to Time.1
> data.frame(BOD[1:2], X=BOD[,1]*seq(6)) gives third column-name X (as X is
now a vector)
> data.frame(BOD[1:2], X=BOD[1:2]*seq(6)) or with BOD[,1:2] gives columns
names X.Time and X.demand, to show these (multiple) columns are coming from X
>
> So I don't think there's much to fix here. I this case having
X.Time in all cases would have been better, but in general the column-naming of
data.frame works, changing it would likely cause a lot of problems.
> You can always change the column-names later.
>
> Best regards,
> Emil Bode
>
> Data-analyst
>
> +31 6 43 83 89 33
> emil.bode at dans.knaw.nl
>
> DANS: Netherlands Institute for Permanent Access to Digital Research
Resources
> Anna van Saksenlaan 51 | 2593 HW Den Haag | +31 70 349 44 50 | info at
dans.knaw.nl <mailto:info at dans.kn> | dans.knaw.nl
<applewebdata://71F677F0-6872-45F3-A6C4-4972BF87185B/www.dans.knaw.nl>
> DANS is an institute of the Dutch Academy KNAW <http://knaw.nl/nl>
and funding organisation NWO <http://www.nwo.nl/>.
>
> ?On 23/07/2018, 16:52, "R-devel on behalf of Gabor Grothendieck"
<r-devel-bounces at r-project.org on behalf of ggrothendieck at gmail.com>
wrote:
>
>     Note the inconsistency in the names in these two examples.  X.Time in
>     the first case and Time.1 in the second case.
>
>       > transform(BOD, X = BOD[1:2] * seq(6))
>         Time demand X.Time X.demand
>       1    1    8.3      1      8.3
>       2    2   10.3      4     20.6
>       3    3   19.0      9     57.0
>       4    4   16.0     16     64.0
>       5    5   15.6     25     78.0
>       6    7   19.8     42    118.8
>
>       > transform(BOD, X = BOD[1] * seq(6))
>         Time demand Time.1
>       1    1    8.3      1
>       2    2   10.3      4
>       3    3   19.0      9
>       4    4   16.0     16
>       5    5   15.6     25
>       6    7   19.8     42
>
>     --
>     Statistics & Software Consulting
>     GKX Group, GKX Associates Inc.
>     tel: 1-877-GKX-GROUP
>     email: ggrothendieck at gmail.com
>
>     ______________________________________________
>     R-devel at r-project.org mailing list
>     https://stat.ethz.ch/mailman/listinfo/r-devel
>
>


-- 
Statistics & Software Consulting
GKX Group, GKX Associates Inc.
tel: 1-877-GKX-GROUP
email: ggrothendieck at gmail.com

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