All graphs can be inspected, used in analysis and even visualized via igraph's C, R or Python interface. 
      Please read the igraph documentation for detailed igraph usage information.
    
      require(igraph)
      graph <- read.graph("path_of_graph.graphml", format="graphml")
    
    To load the graph into Python:
    
    import igraph
    g = igraph.read("path_of_graph.graphml", format="graphml")
    
    To load a graph using C:
    
      #include <igraph.h>
      #include <stdio.h>
      int main(int argc, char **argv) {
        igraph_t g;
        FILE *ifile, *ofile;
        ifile=fopen("path_of_graph.graphml", "r");
        igraph_read_graph_graphml(&g, ifile, 0)
        // Do something with the graph. see http://igraph.org/c/doc/igraph-tutorial.html
        fclose(ifile);
        igraph_destroy(&g)
        return 0;
      }