[R] mean duration (persistence) of daily data

[Schmidt Martin]

Dear R users

A quite simple question: how can I get the mean duration (persistence)  
of daily data, when the data set looks as follows: 

[1] 7 7 7 9 9 5 7 5 5 5 9 5 5 6 6 6 1 1 1 2 2 4 4 4 4 7 7 3 3 2 4 4 7 7 7 7 7
[38] 7 7 5 5 9 9 5 5 5 1 7 9 9 9 9 9 5 5 5 5 5 3 4 4 4 4 4 4 4 4 2 2 2 2 2 2 8
[75] 8 6 6 6 8 8 8 8 8 6 6 2 8 8 8 8 8 8 8 8 8 2 2 2 2 2 6 6 6 6 6 6 6 6 6 6 3
[112] 3 2 2 2 1 5 1 1 4 2 2 2 2 2 2 2 3 4 4 4 3 3 3 6 6 6 8 8 4 4 2 4  
4 1 1 6 6
.............................and so on: 

Thus, I'd like to know, from each number (1-9) the mean duration from  
the first to the last day (here not visible, but each number stands  
for a day).

With:

length(which(test==1))

I certainly get the total number of number 1......unfortunately that's  
all I got!


Thanks for help