[igraph] Mapping Strings to Integers

[S.M. Ali Abbas]

Dear All,
I am quite a newbie to R. Trying to learn it these days. Sorry for asking such a basic question, but could you kindly tell me how to map unique string values to integers in a data frame? I have a graph which has, most of its, vertices' attributes in a string format. I would like to replace them with ascending integers. For example, first unique value in column 1 changes to "0". I'd like to have it so that I could use my computer's resources efficiently and also could easily perform statistical measures on it. I am looking for a two way mapping, so that, after analysis, I could see meaningful results in terms of the same but in reverse order mappings. Hope I was clear in my question.

Thanks!

Cheers,
Ali