Re: Selecting every other line from a data frame

[Tim Hesterberg <timh@insightful.com>]

>I have a large data frame, from which I want to only select every
>other line or odd lines.
>How can I do this?  Thanks.

Some other responses have suggested basically:
        x[ vector of logical values with alternating T/F, ]

I have two comments:

(1) It is safer to add drop=FALSE
        x[ vector of logical values with alternating T/F, , drop=FALSE]
in case the data frame has only one column.

(2) You could instead do e.g.:
        x[ seq(from = 1, to = nrow(x), by=2), , drop = FALSE]
However, you should only do this if the data frame has a dup.row.names
attribute, otherwise this would incur a large performance hit
in checking for duplicated row names in the output.

Tim Hesterberg