[R] idiom for constructing data frame

[Richard M. Heiberger]

I got rid of the extra column.

data.frame(r=seq(8), foo=NA, bar=NA, row.names="r")

Rich

On Tue, Mar 31, 2015 at 6:18 PM, Sven E. Templer <sven.templer at gmail.com> wrote:
> If you don't mind an extra column, you could use something similar to:
>
> data.frame(r=seq(8),foo=NA,bar=NA)
>
> If you do, here is another approach (see function body):
>
> empty.frame <- function (r = 1, n = 1, fill = NA_real_) {
>   data.frame(setNames(lapply(rep(fill, length(n)), rep, times=r), n))
> }
> empty.frame()
> empty.frame(, seq(3))
> empty.frame(8, c("foo", "bar"))
>
> I could not put it in one line either, without retyping at least one
> argument (n in this case).
> So I suggest a function is the way to go for a simplified syntax ...
>
> Thanks to all for the ideas!
> Sven
>
> On 31 March 2015 at 20:55, William Dunlap <wdunlap at tibco.com> wrote:
>
>> You can use structure() to attach the names to a list that is input to
>> data.frame.
>> E.g.,
>>
>> dfNames <- c("First", "Second Name")
>> data.frame(lapply(structure(dfNames, names=dfNames),
>> function(name)rep(NA_real_, 5)))
>>
>>
>> Bill Dunlap
>> TIBCO Software
>> wdunlap tibco.com
>>
>> On Tue, Mar 31, 2015 at 11:37 AM, Sarah Goslee <sarah.goslee at gmail.com>
>> wrote:
>>
>> > Hi,
>> >
>> > Duncan Murdoch suggested:
>> >
>> > > The matrix() function has a dimnames argument, so you could do this:
>> > >
>> > > names <- c("strat", "id", "pid")
>> > > data.frame(matrix(NA, nrow=10, ncol=3, dimnames=list(NULL, names)))
>> >
>> > That's a definite improvement, thanks. But no way to skip matrix()? It
>> > just seems unRlike, although since it's only full of NA values there
>> > are no coercion issues with column types or anything, so it doesn't
>> > hurt. It's just inelegant. :)
>> >
>> > Sarah
>> > --
>> > Sarah Goslee
>> > http://www.functionaldiversity.org
>> >
>> > ______________________________________________
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>> > and provide commented, minimal, self-contained, reproducible code.
>> >
>>
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>>
>> ______________________________________________
>> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
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>> http://www.R-project.org/posting-guide.html
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>>
>
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>
> ______________________________________________
> R-help at 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.