[R] show equal entries in data.frame

[Martin Batholdy]

Hi,

I have the following data-frame:


x <- data.frame(first = c('a','c','k','b'), second = c('b','k','a','j'), third = c('f','a','h','b'))

  first second third
1     a      b     f
2     c      k     a
3     k      a     h
4     b      j     b


Now I would like to see wether there are entries that exists in all three columns.

In the example data-frame this would be true for 'a' and 'b'
(so the row-number of the element is not important).


can someone help me on this?



thanks!