[R] list syntax question: which subscript is which

Carl Witthoft
Tue, 14 Oct 2008 21:49:03 -0000

Hi,
Sorry to bother with something that should be simple, but I can't find it.

Suppose I have a list, each element of which is a 2xN dataframe, where N
could be different for each element.
Is there some simple structure to let me examine all the elements of
each element's first column?  For example:

 >foo
$first
      [,1] [,2]
[1,]    1    4
[2,]    2    5
[3,]    3    6

$second
      [,1] [,2]
[1,]    1    6
[2,]    2    8
[3,]    3    6
[4,]    4    8

To find the maximum element in all first columns (say, to set the range
of a plot where all first columns are x-data), I'd like the legal
equivalent of

 >max(foo[[*]][,1])
(where here "*" is a wildcard intended to span all elements of foo)

Or do I have to use one of the apply() functions?

thanks
Carl