Date:         Mon, 26 Oct 2009 09:41:45 -0400
Reply-To:     Chao Yawo <Yawo1964@YAHOO.COM>
Sender:       "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From:         Chao Yawo <Yawo1964@YAHOO.COM>
Subject:      Need Help Creating a Matrix
Content-Type: text/plain; charset=ISO-8859-1

Hi,

I have a dataset with the following structure.


ColumnA            ColumnB         ColumnC
ClassA            OtherStud        WorkWith

AA                     DD                1
AA                     EE                0
AA                     BB                1
BB                     FF                1
BB                     GG                1
BB                     KK                0
CC                     AA                1
CC                     BB                1


ColumnA refers to students in ClassroomA, and Column B refers to "Other
Students" in the school who could act as work and/or playmates.



Note, ColumnB could also include some of the same students in
ColumnA(ClassA) who work with each other (For example, Students: AA
and BB).

If a Student in Classroom A works with a student in ClassroomB, ColumnC
takes the value of 1, and 0(zero) if otherwise

So, looking at ColumnA, we find that there are three students:  AA, BB and
CC. Student_AA for instance interacts with three students <DD, EE, BB> but only
works with DD and BB.  Similarly, Student_CC interacts with two students
<AA, and BB> and works and plays with each of them.

Now, I am interested in constructing a matrix indicating which
students in ClassroomA work with each other. This means
that student_AA for instance works with student_BB, who is in his/her
classroom, hence the cell in their matrix will have a "1".

Again, Student_CC in ClassroomA works with 2 other members of
his/her own class<ie, AA and BB>.  So CC would have two "1s" in the matrix.

The resulting matrix for the "Works With" relation (ColumnC) among the 3
students in ClassroomA would look like this.

        AA    BB      CC
AA      0     1        0
BB      0     0        0
CC      1     1        0

This matrix is the output I am interested in, and need to produce for
the relationship specified in Column C.

I would certainly appreciate some ideas to help me produce this.


Thanks in advance for your assistance.

Sincerely, Cy


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