[R] transforming column of a dataframe by var- and median-functions

[Agrarimmobilien]

Hello,

I try to transform a data frame like

A        B        C

1        1        2,5
2        2        NA
3        1        1,0
4        1        56
5        2        23
6        1        NA
7        2        46

to the following dataframe, calculating the variance and median of the 
C-column, group by B, so the result will be:

B        C(median)         D (var)
1        19,83                9
2        34,5                21


Doing this, I got problems with the NAs in column C.
I tried to combine the aggregate - function
aggregate(C, list(B), FUN=(mean, var))

with the following functions

var(C, use="complete.obs")
median(C, rm.na=TRUE)

but it doesn't work as I want. Has anybody an idea how to do this work?

thank you
Iksmax