R - basic function - Rank of a vector within a matrix, by observation

Question

I would like to perform the rank of a column vector within a matrix.

I have the following matrix "data"

> data <- matrix (c(12,43,15,17,15,23,4,50,43,6,91,8), nrow = 4, ncol = 3)

With names and date it should look like this

Date  Obs     y1   y2   y3

2014   1      12   15   43 
2014   2      43   23   6
2013   1      15   4    91
2013   2      17   50   8

output should be the rank of a variable against other variables, for each unique observation (date*Obs)

Date  Obs        formula(y1)  formula(y2)  formula(y3)

2014   1         3            2            1
2014   2         1            2            3
2013   1         2            3            1
2013   2         2            1            3

EDIT : Thanks to @Tim Hoolihan and user20650, for a simple matrix is : t(apply(data, 1, function(x) rank(-x)))

Thank you for the help - from a lost noob.

Answer 1

Use apply to iterate over the rows and rank them:

> data <- matrix (c(12,43,15,17,15,23,4,50,43,6,91,8), nrow = 4, ncol = 3)
> t(apply(data, 1, function(x) rank(-x)))
     [,1] [,2] [,3]
[1,]    3    2    1
[2,]    1    2    3
[3,]    2    3    1
[4,]    2    1    3