[R] I need a very specific unique like function and I don't know even how to properly call this

[Phil Spector]

Given a vector, x, we can test if the value above
it is equal to itself with

    abv = c(FALSE,x[-l] == x[-1])

and if the value below is equal to itself with

    blw = c(x[-l] == x[-1],FALSE)

So, for your problem:

> abv = c(FALSE,dat[,2][-l] == dat[,2][-1])
> blw = c(dat[,2][-l] == dat[,2][-1],FALSE)
> dat[!(abv & blw),]
      [,1] [,2]
[1,]    3    7
[2,]    6    5
[3,]    5    5
[4,]    8    4
[5,]    7    4
[6,]    0    6

 					- Phil Spector
 					 Statistical Computing Facility
 					 Department of Statistics
 					 UC Berkeley
 					 spector at stat.berkeley.edu


On Mon, 22 Nov 2010, madr wrote:

>
> consider this matrix:
>
>      [,1] [,2]
> [1,]    3   7
> [2,]    6   5
> [3,]    7   5
> [4,]    3   5
> [5,]    7   5
> [6,]    5   5
> [7,]    8   4
> [8,]    2   4
> [9,]    7   4
> [10,]    0   6
>
> I need to delete all rows where column 2 above and below has the same value,
> so the effect would be:
>
>      [,1] [,2]
> [1,]    3   7
> [2,]    6   5
> [6,]    5   5
> [7,]    8   4
> [9,]    7   4
> [10,]    0   6
>
> is there a built in function for that kind of operation or I must write one
> from scratch ?
> Is there a name for that kind of operation ?
> -- 
> View this message in context: http://r.789695.n4.nabble.com/I-need-a-very-specific-unique-like-function-and-I-don-t-know-even-how-to-properly-call-this-tp3054427p3054427.html
> Sent from the R help mailing list archive at Nabble.com.
>
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