Extract rows with similar rownames from two files

Question

In R, how can extract rows with identical row names from two data frames?

Answer 1

If you have two data frames d1 and d2, the row names that are identical in both are given by intersect(rownames(d1), rownames(d2)). So you can do for example d1[intersect(rownames(d1), rownames(d2)), ] and get rows in d1 that exist in d2