[R] simple question on picking out some rows of a matrix/data frame

[Spencer Graves]

      One alternative that I use is illustrated in the following examples: 

 > DF[DF$x==DF$y, ]
   x  y z
1 -1 -1 a
4  1  1 d
 >
 > sel <- (DF$x != DF$y)
 > DF[sel,]
   x  y z
2  1 -1 b
3 -1  1 c

       hope this help. 
      spencer graves

Douglas Bates wrote:

>"subset" will do the selection.  If you really want a matrix for the
>result you will need to coerce it using "as.matrix".
>
>Roger Levy <rog at stanford.edu> writes:
>
>  
>
>>I have a simple question about matrix/data frame manipulation.  I have
>>a data frame that looks a something like this
>>
>>  X    Y    Z
>>  1    0    "apples"
>>  -1   -1   "oranges"
>>  ...
>>  0    -1   "bananas"
>>
>>and I'd like to pull out all the rows for which X and Y are (un)equal
>>into a submatrix.
>>
>>How can I do that?
>>
>>Many thanks,
>>
>>Roger Levy
>>    
>>
>
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