Dear Rui,
Thank you so much. Yes, that function is what I wanted.
I will make sure I post a data example for the next time.
Thank you for your help again.
Bests,
Seungyeul
On Jun 7, 2012, at 12:50 PM, Rui Barradas wrote:
> Hello,
>
> You should post a data example, like the posting guide says. If your dataset
> is large, use something like
>
> dput(head(dat, 20)) # paste the output of this in your post.
>
>
> where 'dat' is your dataset.
> Now, try
>
>
> # make up some data
> set.seed(12)
> dat <- matrix(c(sort(rnorm(10)), sample(letters[1:4], 10, TRUE)), ncol=2)
> colnames(dat) <- c("A", "col10")
> dat
>
> # this does it
> ix <- as.logical(ave(seq_len(nrow(dat)), dat[, "col10"],
> FUN=function(x) ifelse(x == min(x), TRUE, FALSE)))
> dat[ix, ] # rows 1, 2, 4, 6
>
>
> Hope this helps,
>
> Rui Barradas
>
> Em 07-06-2012 17:07, Seungyeul Yoo escreveu:
>> Hi all,
>>
>> I have a matrix with 10000 rows and 10 columns. The last columns contains
>> another identifiers but the values are not uniques so that I want to
>> generate another matrix with rows with unique values in the last column.
>>
>> If I did
>>
>> tmp<-unique(my_mat$col10)
>>
>> this will give me 8560 unique entries so the ideal matrix will be 8560X10
>> columns now then.
>>
>> I tried
>>
>> sub_mat<-my_mat[tmp,]
>>
>> but it generated weird results with many "NA" values and the order was not
>> changed. The original matrix was ranked from top so I don't want to lose the
>> order too.
>>
>> For the similar problem, I have used "match" function and do some manipulate
>> to identify the index of the first appearance of each value but is there any
>> better and neat way to achieve the same function?
>>
>> Thanks,
>>
>> Seungyeul Yoo
>>
>> Postdoc Fellow,
>> Institute of Genomics and Multiscale Biology
>> Department of Genetics and Genomic Sciences
>> Mount Sinai School of Medicine
>>
>> ______________________________________________
>> 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.
>>
>
______________________________________________
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.
