Tuple index out of range problem

[102jon]

I'm writing a script that essentially splits a polygon (a list of coordinate pairs) into two for a given special case. For the first polygon I run a for loop as follows:

code:

for i in range(1, len(polygon)):                          if (polygon[i][0] < 0) and (polygon[i+1][0] > 0):                 boundIntercept = polygon[i][1] - ((polygon[i][1] - polygon[i+1][1]) / (polygon[i][0] - polygon[i+1][0])) * polygon[i][0]                 newPolygon1[i] = (0, boundIntercept)                            elif (polygon[i-1][0] > 0) and (polygon[i][0] < 0):                 boundIntercept = polygon[i][1] - ((polygon[i][1] - polygon[i-1][1]) / (polygon[i][0] - polygon[i-1][0])) * polygon[i][0]                 newPolygon1[i] = (0, boundIntercept)             elif ((polygon[i][0] < 0) and (polygon[i-1][0] < 0) and (polygon[i+1][0] < 0)):                 newPolygon1[i] = None         firstPolygon = [item for item in newPolygon1 if item != None]

No problem there. However, I do the exact same thing for the second polygon:

code:

for i in range(1, len(polygon)):             if (polygon[i][0] > 0) and (polygon[i+1][0] < 0):                 boundIntercept = polygon[i][1] - ((polygon[i][1] - polygon[i+1][1]) / (polygon[i][0] - polygon[i+1][0])) * polygon[i][0]                 newPolygon2[i] = (0, boundIntercept)             elif (polygon[i-1][0] < 0) and (polygon[i][0] > 0):                 boundIntercept = polygon[i][1] - ((polygon[i][1] - polygon[i-1][1]) / (polygon[i][0] - polygon[i-1][0])) * polygon[i][0]                 newPolygon2[i] = (0, boundIntercept)             elif ((polygon[i][0] > 0) and (polygon[i-1][0] > 0) and (polygon[i+1][0] > 0)):                 newPolygon2[i] = None         secondPolygon = [item for item in newPolygon2 if item != None]

And I get a "error: tuple index out of range". Any insight would be appreciated.

[DemonWasp]

It would be easier for us to help if you also listed the initialization of the two polygons, and if your code were properly indented in your [ code ] elements.

[102jon]

I figured it out, but thanks. The code was indented properly but something happened when copying and pasting it here.