[R] data network format and grouping analysis

[Sebastián Daza]

Hi everyone,
I have a dataset of friendship with this format:

      ego alter
4746    1     2
9742    1     3
14738   1    NA
4747    2    NA
9743    2    3
14739   2    1
4748    3    13
9744    3   5
14740   3    14
4749    4    NA
9745    4    NA
14741   4    NA
4750    5    NA
9746    5    13
14742   5    10
4751    6   12
9747    6     7
...


NA means that individuals don't select any friend. Does anyone know how 
to format this dataset to use sna or igraph packages? I don't know how 
to convert it into a matrix or a edgelist in R without losing isolated 
individuals .

Next question, anyone knows if there is a package to perform a  Moody's 
Crowds routine to identify groups using R, or other algorithms designed 
to search groups by maximizing modularity scores?

Thank  you in advance!

-- 
Sebastián Daza
sebastian.daza at gmail.com