[R] Select the same rows

[sangduan jansomboon]

Hi all,
I have a problem selecting some rows from a random data.
I'd like to select the same rows (before 0) .

For example:
A
     
[1]  0 
[2]  1 
[3]  2 
[4]  0 
[5]  1 
[6]  0 
[7]  1 
[8]  2 
[9]  3 
[10] 4

I'd like to select the row where a = 2 1 4 

I searched on the search of the R site but I did'nt find anything of simple.
Can someone help me?

Thank you very much
Seangduan