[R] Identifying integers (as opposed to real #s) in matrix

[Romain Francois]

Le 10/08/10 10:05, David Katz a écrit :
>
> Is there a way to identify (for subsequent replacement) which rows in a
> matrix are comprised entirely of *integers*?  I have a large set of
> *nx3 *matrices
> where each row either consists of a set of 3 integers or a set of 3 real
> numbers.  A given matrix might looks something like this:
>
>             [ ,1]               [ ,2]               [ ,3]
>
> [1, ]     121.0000        -98.0000       276.0000
>
> [2, ]      10.1234         25.4573         -188.9204
>
> [3, ]      121.0000        -98.0000       276.0000
>
> [4, ]      -214.4982       -99.1043        -312.0495
>
> .....
>
> [n, ]      99.0000          1.0000           -222.0000
>
> Ultimately, I'm going to replace the values in the integer-only rows with
> "NAs."  But first I need r to recognize the integer-only rows.  I assume
> whatever function I write will be keyed off of the ".0000s", but have no
> clue how to write that function.  Any ideas?
>
> David Katz

Something like this perhaps:

 > x <- rbind( c(1, 2, 3), c(1.2,2.2, 3.2), c(1,2,3), c(1.2, 1.2, 1.3 ) )
 > x
      [,1] [,2] [,3]
[1,]  1.0  2.0  3.0
[2,]  1.2  2.2  3.2
[3,]  1.0  2.0  3.0
[4,]  1.2  1.2  1.3

 > rowSums( x == round(x) ) == ncol(x)
[1]  TRUE FALSE  TRUE FALSE

 > x[ rowSums( x == round(x) ) == ncol(x) , ] <- NA
 > x
      [,1] [,2] [,3]
[1,]   NA   NA   NA
[2,]  1.2  2.2  3.2
[3,]   NA   NA   NA
[4,]  1.2  1.2  1.3


Romain

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Romain Francois
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