[R] Does R have an equivalent for Matlab's cell array?

[Matthijs Daelman]

Hi

I have a time series of measurements: every 10 min. a value was logged.

The data look like:

20100914 08:01     3.74
20100914 08:11     3.74
20100914 08:21     3.71
20100914 08:31     4.39
20100914 08:41     3.74

This data spans several months.

I would like to group the data per day. In Matlab it is fairly easy to 
obtain a cell array, of which the first column contains the date of each 
day, and the second column contains a vector, that in its turn contains 
all values for the corresponding day.

That looks like

14-9-2010    [3.74 3.74 3.71 4.39 3.74...]
15-9-2010    [...]
and so on.

Is it possible to create a similar data structure in in R? I was 
thinking of a data frame, similar to the Matlab's cell array, but it 
doesn't look like data frames can contain vectors. Something like a two 
dimensional list would do the trick, I believe, but does that exist?

Thanks

Kind regards

Matthijs Daelman