name="GreatIcosahedron";
str=ToString[N[2 PolyhedronData[name,"VertexCoordinates"],4]];
StringReplace[str,{" "->"","{"->"","},"->", ","}"->""}]

str=ToString[PolyhedronData[name,"FaceIndices"]-1];
StringReplace[str,{" "->"","{"->"[","}"->"]"}]

PolyhedronData["KeplerPoinsot"]

PolyhedronData[name]