Retain only rows present in all matrices
list, matrix, r, subset
Solution
r <- Reduce(intersect, lapply(my.list, rownames))
my.list.subsetted <- lapply(my.list, function(m) m[r, ])
Problem
Suppose one has a list of matrix objects of different lengths, but some row names in common. How could one retain only those rows present in all matrices? I.e., starting with this: ``` > my.list $matrix.a X1 X2 X3 row.A 59 36 9 row.B 54 29 44 row.C 59 36 9 row.D 54 88 32 $matrix.b X1 X2 X3 row.B 47 12 2 row.C 11 36 9 row.D 54 23 99 $matrix.c X1 X2 X3 row.A 95 31 77 row.B 63 29 44 row.C 60 43 2 ``` And producing this: ``` > my.list.subsetted $matrix.a X1 X2 X3 row.B 54 29 44 row.C 59 36 9 $matrix.b X1 X2 X3 row.B 47 12 2 row.C 11 36 9 $matrix.c X1 X2 X3 row.B 63 29 44 row.C 60 43 2 ``` I suspect that one could use `subset()` and the `%in%` operator but I can't seem to find the exact solution.