> read.table(textConnection(gsub("\\(|\\)", "", var) )) #from prior
posting
V1 V2
1 p1 10
2 p1 3
3 p1 4
4 p2 20
5 p2 30
6 p2 40
7 p3 4
8 p3 1
9 p1 2
> ridxs <- sample(1:nrow(df),floor(0.7*nrow(df)) ) # the 70% sample
row IDs
> df[ridxs,]
V1 V2
5 p2 30
6 p2 40
2 p1 3
7 p3 4
4 p2 20
8 p3 1
>
>
> df[-ridxs,]
V1 V2
1 p1 10
3 p1 4
9 p1 2
The terms to pay particular attention to in the introductory material
are row indexing, dataframe, and negative indexing of dataframes.
On Jan 18, 2009, at 12:35 PM, S.Putoto wrote:
Hello dear R Users,
I am working on a dataset of 928 Enterprises, of which are observed 12
different characters. I need to randomly sample, without repetition,
70% of
the entreprises, to create a testing set, and let the other 30% of the
enterprises be a validating set (holdout validation, I think that
is). How
do I do that? Of course all the characters of each row must remain
together.
Also, I am not very familiar with the R-Base language (it is the
first time
I use it) so if You could also explain to me what every function and
argument means, it would be great help to then reiterate the
procedure.
Really! Don't you that is a bit much? There are many tutorials
available on line. The terms to pay particular attention to in the
introductory material are indexing, dataframe, and negative indexing
of dataframes.
--
David Winsemius
Thank You very much,
Sebastiano
--
View this message in context:
http://www.nabble.com/Extracting-random-rows-from-a-dataset-tp21530539p21530539.html
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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.
