R help - Nov 2008 - unique columns in a matrix and number of each

I need help determining the unique columns of a matrix and the numbers of each
unique column.  For example, let's say I have a matrix with 6 columns, 2 of
these are filled with the value of 1 and the other 4 are filled with the value
of 0.  I would then like to have a command that tells me what the unique columns
are (so columns with 1s and columns with 0s) and the number of each type of
column (so 2 columns of 1s and 4 columns of 0s) that occur in the matrix.

Thank you for any help anyone can provide!!  I have been very impressed with the
help that I have received so far!!  Thank you!

One way is to 'paste' together the values in a column and then use
'table' to count them.

'duplicated' can probably do the same thing with the MARGIN option to
find the duplicated one.  You still them have to find the original
ones.

On Sat, Nov 22, 2008 at 3:42 PM, Salas, Andria Kay <aks2515 at uncw.edu>
wrote:
> I need help determining the unique columns of a matrix and the numbers of
each unique column.  For example, let's say I have a matrix with 6 columns,
2 of these are filled with the value of 1 and the other 4 are filled with the
value of 0.  I would then like to have a command that tells me what the unique
columns are (so columns with 1s and columns with 0s) and the number of each type
of column (so 2 columns of 1s and 4 columns of 0s) that occur in the matrix.
>
> Thank you for any help anyone can provide!!  I have been very impressed
with the help that I have received so far!!  Thank you!
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem that you are trying to solve?

Define inner as in:
http://tolstoy.newcastle.edu.au/R/e4/help/08/08/19562.html
and use that with identical to define an inner product:

m <- matrix(c(1, 2, 1,  2, 3, 2), 2) # test matrix
m
colSums(inner(m, u <- unique(m,,2), identical))
u

Please provide actual code to create test examples and expected results
when you post. Read the last line to every message in r-help and the
posting guide.


On Sat, Nov 22, 2008 at 3:42 PM, Salas, Andria Kay <aks2515 at uncw.edu>
wrote:
> I need help determining the unique columns of a matrix and the numbers of
each unique column.  For example, let's say I have a matrix with 6 columns,
2 of these are filled with the value of 1 and the other 4 are filled with the
value of 0.  I would then like to have a command that tells me what the unique
columns are (so columns with 1s and columns with 0s) and the number of each type
of column (so 2 columns of 1s and 4 columns of 0s) that occur in the matrix.
>
> Thank you for any help anyone can provide!!  I have been very impressed
with the help that I have received so far!!  Thank you!
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>