Using R, how to pivot/transform a dataset whose elements are the result of a function

Question

I have the following toy dataset:

z <- c(2,2,3,3,3,4,2,2)
y <- c(6,6,6,5,4,6,6,5)
x <- c(1,1,2,3,5,4,4,3)
df <- cbind(x,y,z)

I would like to figure out how many times an element z appears with an element x for each element y. The resulting dataset should look like the following:

     y(4) y(5) y(6)
x(1)  0    0    2
x(2)  0    0    1 
x(3)  0    2    0
x(4)  0    0    2
x(5)  1    0    0

The solution needs to be scalable such that the number of elements in x,y, and z is irrelevant.

Every instance where z exists for (Xn, Yn) is counted and summed in the table — SocraticDatum, Sep 11 '14 at 22:53
You will get same result even you would delete `z` column, so I don't know what you mean — David Arenburg, Sep 11 '14 at 22:55

Rich Scriven · Accepted Answer · 2014-09-11T23:03:18.583

3

Your desired result is just a table of x and y.

> table(df[,"x"], df[,"y"])
#   
#    4 5 6
#  1 0 0 2
#  2 0 0 1
#  3 0 2 0
#  4 0 0 2
#  5 1 0 0

Maybe converting df to a data.frame might make more sense

> df <- data.frame(df)
> with(df, table(x, y))
#    y
# x   4 5 6
#   1 0 0 2
#   2 0 0 1
#   3 0 2 0
#   4 0 0 2
#   5 1 0 0

edited Sep 11 '14 at 23:03

answered Sep 11 '14 at 20:28

Rich Scriven

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as.data.frame.matrix(with(df, table(x,y))) is exactly what I was look for. Thanks! – SocraticDatum Sep 11 '14 at 22:51

Using R, how to pivot/transform a dataset whose elements are the result of a function

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