Retain only one line per factor if it meets criteria R

Question

I have a dataset that looks like this:

ID  week  action
1   1     TRUE
1   1     FALSE
1   2     FALSE 
1   2     FALSE
1   3     FALSE
1   3     TRUE
2   1     FALSE
2   2     TRUE
2   2     FALSE
...

What I'd like to do is retain for each ID and each week within ID, one value of action, with preference to retaining a TRUE if there is one, else a FALSE.

So it would look like this when through:

ID  week  action
1   1     TRUE
1   2     FALSE
1   3     TRUE
2   1     FALSE
2   2     TRUE
...

Answer 1

I used plyr:

library(plyr)
ddply(df,.(ID,week),summarize,action=sum(action)>0)