Re: [R] merge function in R

From: Don MacQueen <macq_at_llnl.gov>
Date: Tue 06 Jun 2006 - 00:27:29 EST

(See insertions below)

At 8:49 PM -0300 6/2/06, Juan Santiago Ramseyer wrote:
>Em Qui, 2006-06-01 às 05:59 -0700, Ahamarshan jn escreveu:
>> hi list,
>>
>> This question must be very basic but I am just 3 days
>> old to R. I am trying to find a function to merge two
>> tables of data in two different files as one.
>>
>> Does merge function only fills in colums between two
>> table where data is missing or is there a way that
>> merge can be used to merge data between two matrixes
>> with common dimensions.
>>
>> say i have
>>
>> v1 v2 v3 v4
>> h1
>> h2
>> h3
>> h4
>> h5
>>
>> and and another table with
>>
>> x1 x2 x3 x4
>> h1
>> h2
>> h3
>> h4
>> h5
>>
>>
>> can i merge the data as
>>
>> v1 x1 v2 x2 v3 x3 v4 x4
>> h1
>> h2
>> h3
>> h4
>> h5
>>
>> Thanks
>>
>hi
>
>testing the following sequence
>
># matrix examples
>x <- seq(from=-1,to=-20,step =-1)
>v <- seq(1:20)
>dim(x) <- c(5,4)
>dim(v) <- c(5,4)
>
>vx <- rep(NA,times=40)
>dim(vx) <- c(5,8)
>
># answer init
>for (i in 1:4) {
> vx[,2*i-1] <- v[,i]
> vx[,2*i] <- x[,i]
>}
># answer end

The loop is more complicated than necessary.

vx2 <- matrix(numeric(40),ncol=8)
vx2[,c(1,3,5,7)] <- v
vx2[,c(2,4,6,8)] <- x

## or more generally
vx2[ ,seq(1,by=2,len=4)] <- v
vx2[ ,seq(2,by=2,len=4)] <- x

## if the order of columns did not matter then the simplest is vx3 <- cbind(v,x)

-Don

>Juan Santiago Ramseyer
>Eng. Recursos Hídricos
>
>
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>
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA

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Received on Tue Jun 06 00:36:26 2006

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