[R] Repeating lines in a data frame

[Guenther, Cameron]

Hello,
I have a much larger dataset that is similar in form to:
 year species length count
 1998       1    150     1
 1998       2    200     1
 1998       3    250     2
 1999       1    150     3
 1999       2    200     4
 1999       3    250     5
 2000       1    150     1
 2000       2    200     1
 2000       3    250     1
 2001       1    150     2
 2001       2    200     3
 2001       3    250     1
 2002       1    150     1
 2002       2    200     2
 2002       3    250     3

What I want is to have a line of data for each year x species x length
group combination
I would like the ouput to be:

Year species length count
1998       1    150     1
1998       2    200     1
1998       3    250     1
1998       3    250     1
1999       1    150     1
1999       1    150     1
1999       1    150     1
1999       2    200     1
.
.
.

Can anyone help me with a for statement of a function that can
accomplish this?
Thanks

Cameron Guenther 
Associate Research Scientist
FWC/FWRI, Marine Fisheries Research
100 8th Avenue S.E.
St. Petersburg, FL 33701
(727)896-8626 Ext. 4305
cameron.guenther at myfwc.com