To slightly correct what's been said: In general
lists are linear objects, but a list can have
dimension.
An example is in Circle 8.1.8 of 'The R Inferno'.
http://www.burns-stat.com/pages/Tutor/R_inferno.pdf
Pat
On 16/08/2012 21:50, Schumacher, Jay S wrote:
are these
hi,
i'm trying to understand r data structures. i see that vectors, matrix,
factors and arrays have a dimension.
there seems to be no mention of dimensionality anywhere for lists or
dataframes. can i consider lists and frames to be of fixed dimension 2?
thanks,
jay s
Hi,
On Thu, Aug 16, 2012 at 2:49 PM, Schumacher, Jay S j...@neo.tamu.edu wrote:
hi,
i'm trying to understand r data structures. i see that vectors, matrix,
factors and arrays have a dimension.
Out of curiosity, where do you see that vectors and factors have a
dimension? I mean -- I
On Aug 16, 2012, at 11:49 AM, Schumacher, Jay S wrote:
hi,
i'm trying to understand r data structures. i see that vectors,
matrix, factors and arrays have a dimension.
there seems to be no mention of dimensionality anywhere for lists
or dataframes. can i consider lists and frames to
It would be helpful to distinguish between a formal dimension attribute,
and a (personal) conceptual model of whether or not any particular R
object, or type of object, has dimension. Mention of data frames having
dimension can be found in the help page for the dim() function.
foo - 1:10
are these correct/accurate/sensible statements:
a vector is a one dimensional object.
a matrix is a two dimensional object.
a list is a one dimensional object.
i'm working from this web page:
http://www.agr.kuleuven.ac.be/vakken/statisticsbyR/someDataStructures.htm
On Thu, Aug 16, 2012 at 4:50 PM, Schumacher, Jay S j...@neo.tamu.edu wrote:
are these correct/accurate/sensible statements:
a vector is a one dimensional object.
a matrix is a two dimensional object.
a list is a one dimensional object.
i'm working from this web page:
yes, thank you, conceptual model (rather than formal dimension attribute)
is where i'm coming from at this point.
It would be helpful to distinguish between a formal dimension attribute,
and a (personal) conceptual model of whether or not any
On Aug 16, 2012, at 1:50 PM, Schumacher, Jay S wrote:
are these correct/accurate/sensible statements:
a vector is a one dimensional object.
a matrix is a two dimensional object.
a list is a one dimensional object.
i'm working from this web page:
I don't disagree with Michael, but I would add that to me it also depends.
If one thinks in terms of subsetting an object (for objects that can be
subsetted)
To subset a vector, one supplies *one* value for the index:
myvector[3]
myvector[ 2:5 ]
are valid statements.
Similarly for a list
On Thu, Aug 16, 2012 at 5:44 PM, MacQueen, Don macque...@llnl.gov wrote:
Whereas for a matrix or data frame, one must supply *two* index values
(even if one of them may be omitted)
mydf[ 1 , 3 ]
mydf[ , 5 ]
mymat[ 2:5 , ]
mymat[ 3 , 4:6 ]
are valid statements.
Not quite:
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