title: Graph-tool: subgraphs as new Graph objects
body: <p>I find graph-tool documentation extremely obscure and much more cryptic than other analogous libraries.</p>
  
  <p>I really can't figure out how to "extract" components (aka connected components) from a graph in graph-tools. I would like to save subgraphs in separate files as separate Graphs but I don't understand how to identify them starting from my Graph object.</p>