[R] Deleting rows with special character

Peter Kupfer peter.kupfer at me.com
Fri Nov 16 15:32:23 CET 2012


Hey Sara,
first: Thanks for the fast reply! I checked the apply function and I found my error. 
For sure: I forgot to send an sample data. After sending the mail I recognized it. Sorry about this! 
Once again: Thanks for the fast reply and your help.
Best
Peter



Am 16.11.2012 um 15:26 schrieb Sarah Goslee <sarah.goslee at gmail.com>:

> Hi Peter,
> 
> On Fri, Nov 16, 2012 at 9:04 AM, Peter Kupfer <peter.kupfer at me.com> wrote:
>> Dear all,
>> maybe a simple problem but I found no solution for my problem.
>> I have a matrix Y with 23 000 rows and 220 colums. The entries are "A", "B" or "C".
> 
> A reproducible example with sample data is helpful.
> 
>> I want to extract all rows (as a matrix ) of the matrix Y where all entries of a row are (for example) "A".
> 
> Really? Why not just make a new matrix with the right number of "A" values?
> 
>> Is there any solution? I tried the stringr- package but i doesn't work out.
> 
> Of course there is. Here's one option. But I'm not sure you've really
> stated your actual problem. This extracts the rows where all values
> are "A", and might at least get you started toward your real problem.
> 
> testdata <- matrix(c(
> "A", "B", "C",
> "B", "B", "B",
> "C", "A", "A",
> "A", "A", "A"),
> ncol=3, byrow=TRUE)
> 
> testdata.A <- testdata[apply(testdata, 1, function(x)all(x == "A")), ,
> drop=FALSE]
> 
> 
> 
> --
> Sarah Goslee
> http://www.functionaldiversity.org




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