[R] extracting rows and columns from a big matrix

[jim holtman]

Is this what you want:

> x <- read.table(text = " X1 X7 X12 X15 X22 X26 X31 X34 X39 X44 X51
+ X1 1 2 3 4 5 6 7 8 9 10 11
+ X7 11 9 7 5 3 1 10 8 6 4 2
+ X12 3 4 7 8 5 7 2 9 1 3 2
+ X15 9 9 8 4 7 1 1 3 2 5 3
+ X22 6 7 7 4 4 2 9 8 8 1 1
+ X26 3 9 4 8 5 7 6 1 2 3 8
+ X31 1 2 1 3 1 4 1 5 1 6 1
+ X34 6 7 8 5 2 9 5 1 6 8 9
+ X39 4 8 7 4 6 5 1 9 2 7 5
+ X44 2 2 2 8 6 7 9 5 3 7 7
+ X51 9 9 9 6 6 4 8 7 2 1 3", header = TRUE)
>
> indx <- c("X1", "X12", "X22", "X31")
> x[indx, indx]
    X1 X12 X22 X31
X1   1   3   5   7
X12  3   7   5   2
X22  6   7   4   9
X31  1   1   1   1


On Sun, Jul 15, 2012 at 3:43 PM, A J <anxusgo at hotmail.com> wrote:
> Sorry so much for mistakes.
>
>
> It was an example code and I commited some mistakes typing it. But meaning
> the original code is right (I have checked several times) I am not sure
> about how to solve the problem of extracting columns and rows using labels
> from a squared matrix. I have enclosed a text file with the idea in order to
> understand it better.
>
>
> Thanks again, and sorry for the inconvenience.
>
>
> Best,
>
>
> AJ
>
>
>
>> Date: Sun, 15 Jul 2012 14:53:47 -0400
>> Subject: Re: [R] extracting rows and columns from a big matrix
>> From: jholtman at gmail.com
>> To: anxusgo at hotmail.com
>> CC: r-help at r-project.org
>>
>> For a start, you are missing a quote and a parenthese on the
>> statement; probably should be: (another quote was also missing)
>>
>> n<-subset(m, select=c("X1", "X7", "X12","X15", "X22", "X26", "X31",
>> "X34", "X39", "X44", "X51", "X58"))
>>
>> Not sure what you want with the rownames; an example would help and
>> post with 'dput'.
>>
>> On Sun, Jul 15, 2012 at 2:47 PM, A J <anxusgo at hotmail.com> wrote:
>> >
>> > Hi there and thanks in advance.
>> >
>> > I have a large symmetrical matrix stored in a text file. After load in R
>> > I would like to extract the same number of columns and rows (symmetrical
>> > submatrix) using their labels.
>> >
>> > I have tried this code in order to extract columns, but R console gives
>> > me the "+" sign at the end of the code, pointing out incomplete command, so
>> > it is not working:
>> >
>> > m<-read.table("C:/backup/symmetrical.csv")
>> >
>> > n<-subset(m, select=c("X1", "X7", "X12", X15", "X22", "X26", "X31",
>> > "X34", "X39", "X44", "x51", "X58)
>> >
>> > Therefore, I have no tried with row names yet.
>> >
>> > Any suggestions? Sorry for the inconvenience. I have read some
>> > information about this but always have the same problem with "+" and I do
>> > not have any idea to follow.
>> >
>> > Best,
>> >
>> > AJ
>> >
>> >
>> >
>> >
>> > [[alternative HTML version deleted]]
>> >
>> > ______________________________________________
>> > R-help at 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.
>>
>>
>>
>> --
>> Jim Holtman
>> Data Munger Guru
>>
>> What is the problem that you are trying to solve?
>> Tell me what you want to do, not how you want to do it.



-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.