Create contrast matrix typically for use with 'estimate' (Wald tests).

contr(p, n, diff = TRUE, ...)

Arguments

p

index of non-zero entries (see example)

n

Total number of parameters (if omitted the max number in p will be used)

diff

If FALSE all non-zero entries are +1, otherwise the second non-zero element in each row will be -1.

...

Additional arguments to lower level functions

Examples

contr(2,n=5)
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 0 1 0 0 0
contr(as.list(2:4),n=5)
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 0 1 0 0 0 #> [2,] 0 0 1 0 0 #> [3,] 0 0 0 1 0
contr(list(1,2,4),n=5)
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 1 0 0 0 0 #> [2,] 0 1 0 0 0 #> [3,] 0 0 0 1 0
contr(c(2,3,4),n=5)
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 0 1 -1 0 0 #> [2,] 0 1 0 -1 0
contr(list(c(1,3),c(2,4)),n=5)
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 1 0 -1 0 0 #> [2,] 0 1 0 -1 0
contr(list(c(1,3),c(2,4),5))
#> [,1] [,2] [,3] [,4] [,5] #> [1,] 1 0 -1 0 0 #> [2,] 0 1 0 -1 0 #> [3,] 0 0 0 0 1
parsedesign(c("aa","b","c"),"?","?",diff=c(FALSE,TRUE))
#> [,1] [,2] [,3] #> [1,] 0 1 0 #> [2,] 0 0 1 #> [3,] 0 1 -1