[R] subsetting data-frame by vector of characters

[Wacek Kusnierczyk]

james perkins wrote:
> Thanks a lot for that. Its the %in% I needed to work out mainly
>
> large didn't mean anything in particular, just that it gets quite long
> with the real data.
> I did mean: names = c("John", "Phil", "Robert")
>
> The only problem is that using the method you suggest is that I lose
> the indexing, ie in the example, instead of:
>
> (index)    Name    Fave.Number
> 1    John    7
> 2    Phil    14
> 3    Robert    23
>
>
> I end up with
>
>
> (index) Name Fave.Number
> 1     John     7
> 3     Phil     14
> 5     Robert 23
>
> This isnt a problem at the moment but I guess it could be if I used
> the table later in loops. Is there an easy way to re-index the table?
strange.  i run this simulated example, and it's ok:

d = data.frame(a=letters[rep(1:5,2)], b=letters[10:1])
d[d$a %in% letters[1:3], ]

you can always add an index column:

d = data.frame(index=1:dim(d)[[1]],d)

vQ