[R] Conversion of column matrix into a vector without duplicates

Chuck Cleland ccleland at optonline.net
Wed Jan 24 14:27:16 CET 2007


Shubha Vishwanath Karanth wrote:
> Hi R,
>  
> I have a matrix A,
> 
> A=
> 
>       [,1] [,2]
> 
> [1,]  a     u
> [2,]  b     v
> [3,]  c     x
> [4,]  d     x
> [5,]  e     x
> 
> I want to put the 2nd column of this matrix in a vector without
> duplicates. i.e., my vector v should be (u, v, x), whose length is 3.
> 
> Can anybody help me on this?

> A <- matrix(c("a","b","c","d","e","u","v","x","x","x"), ncol=2)

> A[,2]
[1] "u" "v" "x" "x" "x"

> unique(A[,2])
[1] "u" "v" "x"

> is.vector(unique(A[,2]))
[1] TRUE

  You probably could have helped yourself by checking the results of
RSiteSearch("duplicate") .

> Thanks in advance
> 
> Shubha.
> 
> 
> 	[[alternative HTML version deleted]]
> 
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-- 
Chuck Cleland, Ph.D.
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