[R] A quesiton on data manipulation

[Tong Wang]

Hi, 
    I have a data set (data frame) describing some features of  the students in a high school  in the following format:

Stu ID        Year         feature 1          feature 2      ............. 
1001         1990     
1001         1991
1001         1992
1002         1990
1002         1991
1002         1992
  

   Some features of  a few of these students are missing,   I would like to ignore those students in my  analysis, but
I really can' t figure out a neat way to do this in R.   I need to remove all the info. of a student (indicated by ID no.) if there 
are NA's in his/her features.  

    Could someone give me a quick tutorial on this ?

I would really appreciate. 

best