Focusing on the final question:
Why does J not treat a column of numbers as a N by 1 'matrix' ie a
vector rather than a list?
If you had asked 'Why does readtable not...' I would have answered that
it might be a bug in readtable, or that you should have some
intermediate verb that would guarantee that you get a table result:
readrank2 =: ,.^:(2 > #@$) @ readtable NB. untested
Following Chris's explanation of where the trouble comes from (that ".
sometimes produces a list, sometimes an atom), another way to force the
behavior you want would be to replace ". by (,@".) which would always
produce a list.
As for 'Why does J not...', how would J know that this list should be
treated as a one-column table, rather than a one-row table, a one-row
brick, etc.?
Henry Rich
On 4/16/2017 2:26 PM, Michael Goodrich wrote:
All,
In using 'readtable' as defined in the primer I find the following
situation:
Reading in a square matrix from a file with each row of numbers on a line I
always get the 'correct' answer when asking about the shape of the read in
data, EXCEPT when the data has only one value per line ie is a vector or
de-generate matrix if you will. In that case the shape comes back with a
single number say N whereas I was expecting it to say 'N 1' and indeed the
read in data is not available for linear algebra operations whereas data
with more that one column is without further ado.
Why does J not treat a column of numbers as a N by 1 'matrix' ie a vector
rather than a list?
(Pardon me if I sound like I am whining ;-)
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