[R] corresponding replicated el of one matrix in another matrix or vector

[Uwe Ligges]

On 23.07.2014 22:15, carol white wrote:
> How to keep the same order of elements as v2 for the new matrix?


Oh, come on, read the help files for the functions I provided!

t(merge(data.frame(V2=v2), as.data.frame(v1), sort = FALSE))

Best,
Uwe Ligges



>> v3
>       [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14]
> [1,] "a"  "a"  "a"  "a" "a"  "c"  "c"  "c"  "c"  "c"   "c"   "c"   "c"
> "c"
> [2,] "1"  "1"  "1"  "1"  "1"  "3"  "3"  "3"  "3"  "3"   "3"   "3"
> "3"   "3"
>       [,15] [,16] [,17] [,18]
> [1,] "c"   "b"   "b"   "b"
> [2,] "3"   "2"   "2"   "2"
>
> instead of
>
> t(merge(data.frame(V2=v2), as.data.frame(v1)))
>     [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13]
> [,14]
> V2 "a"  "a"  "a"  "a"  "a"  "b"  "b"  "b"  "c"  "c"   "c" "c"   "c"   "c"
> V1 "1"  "1"  "1"  "1"  "1"  "2"  "2"  "2"  "3"  "3"   "3"   "3"   "3"   "3"
>     [,15] [,16] [,17] [,18]
> V2 "c"   "c"   "c"   "c"
> V1 "3"   "3"   "3"   "3"
>
>
>
> On Wednesday, July 23, 2014 10:06 PM, Uwe Ligges
> <ligges at statistik.tu-dortmund.de> wrote:
>
>
>
>
> On 23.07.2014 21:16, carol white wrote:
>  > Hi,
>  > I have a matrix of unique elements (strings) like v1 and a vector
> which contains replicated values of the 2nd column of the first matrix.
>  >
>  > v1 = cbind(c("1","2","3"),c("a","b","c"))
>  >
>  > v2 = c(rep("a",5), rep("c",10), rep("b",3))
>  >
>  > How can I add a column to v2 that contains the values of the first
> column of the first matrix v1 where the 2nd column of v1 matches the
> values of v2? Do I need to grep by looping over the nrow of v1 which is
> very time consuming or is there a better solution?
>  >
>  > the results should be the same as
>  >
>  >
>  > v3=rbind( c(rep("a",5), rep("c",10), rep("b",3)), c(rep("1",5),
> rep("3",10), rep("2",3)))
>
>
> I'd try
>
> t(merge(data.frame(V2=v2), as.data.frame(v1)))
>
>
> Best,
> Uwe Ligges
>
>
>
>  > ---------------------------------------------------------------
>  > v1
>  >      [,1] [,2] [,3]
>  > [1,] "1"  "2"  "3"
>  > [2,] "a"  "b"  "c"
>  >> v2
>  >  [1] "a" "a" "a" "a" "a" "c" "c" "c" "c" "c" "c" "c" "c" "c" "c" "b"
> "b" "b"
>  >> v3
>  >      [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12]
> [,13] [,14]
>  > [1,] "a"  "a"  "a"  "a"  "a"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"  "c"
>  > [2,] "1"  "1"  "1"  "1"  "1" "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"  "3"
>  >      [,15] [,16] [,17] [,18]
>  > [1,] "c"  "b"  "b"  "b"
>  > [2,] "3"  "2"  "2"  "2"
>
>  >     [[alternative HTML version deleted]]
>  >
>  >
>  >
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