Actually, what would be even better would be an extra argument to
specify the column names.
I don't think it's very difficult to implement and it would make things
even easier.
Ivan
Le 5/16/2011 11:25, Ivan Calandra a écrit :
Thanks Santosh!
The more I learn about R.utils, the more I think that many of its
functions should be included in the base distribution.
Ivan
Le 5/16/2011 10:42, Santosh Srinivas a écrit :
Hi Ivan, Take a look dataFrame in R.utils ... is that what you want?
from the help file:
Examples
df<- dataFrame(colClasses=c(a="integer", b="double"), nrow=10)
df[,1]<- sample(1:nrow(df))
df[,2]<- rnorm(nrow(df))
print(df)
Thanks,
Santosh
On Mon, May 16, 2011 at 1:42 PM, Ivan Calandra
<ivan.calan...@uni-hamburg.de> wrote:
I feel like I'm always asking this type of questions, but is it
possible to
add a base function that allows creating an empty data.frame, as
matrix()
does?
What I mean would be something like:
create.data.frame(number_of_columns, mode_of_columns).
I think it would make things easier than creating one or several
matrices
and then combining them
Is it possible; does it make sense?
Ivan
Le 5/15/2011 22:17, Bert Gunter a écrit :
Inline below.
On Sun, May 15, 2011 at 11:11 AM, Jan van der Laan<rh...@eoos.dds.nl>
wrote:
Thanks. I also noticed myself minutes after sending my message to the
list.
My 'please ignore my question it was just a stupid typo' message
was sent
with the wrong account and is now awaiting moderation.
However, my other question still stands: what is the
preferred/fastest/simplest way to create a data.fame with given
column
types
and dimensions?
I do not know, but why is simply
data.frame(numeric(10), character(10), integer(10),
stringsAsFactors=FALSE)
not acceptable? Note that if you had, say, 500, numeric (= double) and
100 character columns to add, you might do something like:
z<- matrix(numeric(5000),nr=10)
u<- matrix(character(1000),nr=10)
frm<- data.frame(z,u, stringsAsFactors = FALSE) ## 600 columns
While this might save some typing, it may not be much more efficient
than typing it all out -- maybe just some parsing time is saved. You
can experiment and see.
However, since a data.frame **is** a list with added attributes and a
great deal of the work of the constructor is in constructing and
checking these attributes (e.g. row and column names), I see nothing
terribly inefficient with what you did. It's just a bit obscure. But
maybe someone with greater expertise will set us both straight.
Cheers,
Bert
Regards,
Jan
On 05/15/2011 04:43 PM, Bert Gunter wrote:
In your post, you're missing the final "s" on the stringsAsFactors
argument in the d1 assignment. When I typed it correctly, it
works as
expected.
-- Bert
On Sun, May 15, 2011 at 4:25 AM, Jan van der Laan<rh...@eoos.dds.nl>
wrote:
I use the following code to create two data.frames d1 and d2 from a
list:
types<- c("integer", "character", "double")
nlines<- 10
d1<- as.data.frame(lapply(types, do.call, list(nlines)),
stringsAsFactor=FALSE)
l2<- lapply(types, do.call, list(nlines))
d2<- as.data.frame(l2, stringsAsFactors=FALSE)
I would expect d1 and d2 to be the same, however, in d1 the second
column
is
a factor while in d2 it is a character (which I would expect):
str(d1)
'data.frame': 10 obs. of 3 variables:
$ c.0L..0L..0L..0L..0L..0L..0L..0L..0L..0L.: int 0 0 0 0 0 0
0 0 0 0
$ c........................................: Factor w/ 1 level
"": 1 1
1
1
1 1 1 1 1 1
$ c.0..0..0..0..0..0..0..0..0..0. : num 0 0 0 0 0 0
0 0 0 0
str(d2)
'data.frame': 10 obs. of 3 variables:
$ c.0L..0L..0L..0L..0L..0L..0L..0L..0L..0L.: int 0 0 0 0 0 0
0 0 0 0
$ c........................................: chr "" "" "" "" ...
$ c.0..0..0..0..0..0..0..0..0..0. : num 0 0 0 0 0 0
0 0 0 0
As different but related question: I use the commands above to
create
an
'empty' data.frame with specified column types and dimensions. I
need
this
data.frame to pass on to my c++ routines. Is there a more
simple/elegant
way
of creating this data.frame?
Regards,
Jan
PS:
I am running R on 64 bit Ubuntu 11.04:
sessionInfo()
R version 2.12.1 (2010-12-16)
Platform: x86_64-pc-linux-gnu (64-bit)
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=C 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
______________________________________________
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PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
--
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calan...@uni-hamburg.de
**********
http://www.for771.uni-bonn.de
http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php
______________________________________________
R-help@r-project.org mailing list
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.
--
Ivan CALANDRA
PhD Student
University of Hamburg
Biozentrum Grindel und Zoologisches Museum
Abt. Säugetiere
Martin-Luther-King-Platz 3
D-20146 Hamburg, GERMANY
+49(0)40 42838 6231
ivan.calan...@uni-hamburg.de
**********
http://www.for771.uni-bonn.de
http://webapp5.rrz.uni-hamburg.de/mammals/eng/1525_8_1.php
______________________________________________
R-help@r-project.org mailing list
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.
