[colug-432] python arrays help

[Vince Herried]

for some strange reason I want to create a trefoil knot.
http://en.wikipedia.org/wiki/Trefoil_knot

In blender environment I want to create vertices and edges.
I got part of it working to create the vertices but not the edges.

    27      #############
    28      pi=3.141592654
    29      Vector = mathutils.Vector
    30      width = 16
    31      height = 9
    32
    33      verts = []
    34      edges = []
    35      faces = []
    36
    37      start=0.0
    38      end=pi/2
    39
    40      samples = 35
    41      sampsize=(end-start)/samples
    42
    43
    44      print("samples=",samples)
    45      print("start=",start)
    46      print("end=",end);
    47
    48
    49          # create the vertices and edge loops for cosine
    50      for t in range (samples+1):
    51          x = sin(t) + 2*sin(2*t)
    52          y = cos(t) - 2*cos(2*t)
    53          z = -sin(3*t)
    54          print("x=",x,"y=",y,"z=",z)
    55          v=[Vector(((x * scale_x), (y * scale_y), (z *
scale_z)))]
    56          print("length of v=",len(v))
    57          #verts.append(v)
    58          verts+=v
    59          print("length of verts=",len(verts))
    60          if (t % 2==1):
    61              edges+=[verts[t-1], verts[t]]
    62              #edges.append((verts[t-1], verts[t]))
    63
    64      print("created the verts and edges")
    65      print("len of verts=",len(verts),"len of edges=",len(edges))

line 60 - 63 ain't right.  I don't know how to add the edges.



if I run it to create the mesh without the edges all  is happy
if I add in the edges in the mesh add statement blender complains loudly.
An edge is of course the line between two vertices edge(0) =vert(0)-vert(1)
or is it edge[0] = vert[0]-vert[1].

Blender add mesh statement looks like:
    67      mesh = bpy.data.meshes.new(name="Trefoil Knot")
    68      mesh.from_pydata(verts,[],faces)

or  mesh.from_pydata(verts,edges,faces)   <<--- complains loudly