R help - Oct 2003 - AW: Getting rows from a dataframe

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-----Urspr?ngliche Nachricht-----
Von: Mark Lee [mailto:mark.lee at orbisuk.com] 
Gesendet: Donnerstag, 9. Oktober 2003 18:02
An: r-help at stat.math.ethz.ch
Betreff: [R] Getting rows from a dataframe


Sorry if this is a silly question. I'm trying to extract all elements of a
dataframe at a particular row. I can find no mention of this in any
documentation and it may be naivety of dataframe on my part as I'm very
green at this. Thankyou,

Mark

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I have this right on the desk in front of me. I have gone through most
of this actually and have been looking for the answer for several
weeks now before resorting to this. The only reference I've found to
this is on page 20 under array indexing but didn't see the relation to
dataframes. Thanks,

Mark

If you're having so much trouble, perhaps it's because you want to get a
vector result?  This requires a little more, and if so, perhaps one of the 
following provides what you are looking for:

 > x <- data.frame(a=1:3,b=4:6)
 > # row as a data frame
 > x[2,]
   a b
2 2 5
 > # row as a list
 > x[2,,drop=T]
$a
[1] 2

$b
[1] 5

 > # row as a vector
 > unlist(x[2,,drop=T])
a b
2 5
 > # row as a vector again
 > unlist(x[2,])
a b
2 5
 > # row as a matrix (if x contains any non-numeric columns, this will be a 
character matrix)
 > as.matrix(x[2,])
   a b
2 2 5
 > # row as a vector (if x contains any non-numeric columns, this will be a 
character vector)
 > as.matrix(x)[2,]
a b
2 5
 > # row as a numeric vector (non-numeric columns in x will be converted to 
numeric data, see ?data.matrix for how)
 > data.matrix(x[2,])
   a b
2 2 5
 >

Tony Plate

At Thursday 05:40 PM 10/9/2003 +0100, Mark Lee wrote:
>I have this right on the desk in front of me. I have gone through most
>of this actually and have been looking for the answer for several
>weeks now before resorting to this. The only reference I've found to
>this is on page 20 under array indexing but didn't see the relation to
>dataframes. Thanks,
>
>Mark
>
>______________________________________________
>R-help at stat.math.ethz.ch mailing list
>https://www.stat.math.ethz.ch/mailman/listinfo/r-help