Message-ID: <op.ulk2y7qvw9ljuw@tir-070312.staff.few.eur.nl>
Date: 2008-12-03T11:17:21Z
From: Vitalie S.
Subject: Bug in "transform"?
In-Reply-To: <alpine.LFD.2.00.0812030845540.21836@gannet.stats.ox.ac.uk>
Many thanks for your kind responses.
> That's a simple change and will make transform.data.frame behave more
> consistently with cbind.data.frame and data.frame.
>
Related to above, I find rather inconsistent following behavior:
> aq <- airquality[sample(1:153,6),]
> data.frame(aq, list(a=1,b=2))
Error in data.frame(aq, list(a = 1, b = 2)) :
arguments imply differing number of rows: 6, 1
> cbind(aq,list(a1=1,a2=2))
Error in data.frame(..., check.names = FALSE) :
arguments imply differing number of rows: 6, 1
but,
aq[c("a","b")]<-list(1,2) #works fine
In my understanding all versions above are conceptually similar and should
behave in a same way, and recycling for one row data.frames should be a
default. R is an interactive language and behavior like above is a real
pain.
>>> Just learn to use indexing: transform() is just syntactic sugar that
>>> you are not making use of.
>>>
I really try to use indexing in code all the time I possibly can. But for
interactive use with dozens of data transformations and reshapings per day
- with just indexing I would probably see stars at the end of the day.
Thanks for existence of such "syntactic sugars" and for packages like
Hadley's reshape and plyr.
Regards,
Vitalie.