Q:

Finding intersection of dataframe rownames

I have two dataframes. The row names in both are dates. What I want to do is, I want to select all the common rows (having same dates) in both the data frames and create a new data frame having only these common rows.
Of course the individual columns would get appended next to each other.
Can anyone please help??

A:

Try:
merge(df1, df2, by="row.names")
?merge

Can also use by=0 instead of 'row.names'. And BTW the rownames are not R Date class, but are character valued. I suppose one could also do this:
 cbind( df1[ intersect(rownames(df1), rownames(df2)), ] ,
        df2[ intersect(rownames(df1), rownames(df2)), ] )

