Think about a good way to store node degrees R friendly

We need to save the degree of every vertex for every graph, so that we can plot degree distribution density functions in R. Because graphs have different orders, i.e. different amount of vertices, using a "square" format like a csv file can be cumbersome. Maybe something like this:

0.gr   1.gr ...

d1 4 1 ... d2 2 1 ... . . . . . . . . .

Because then R can select a graph and group by degree.