How to delete specific edge using python?

Question

Firstly, I am new to Blender. I am actually working on to create a hemispherical model with cell fractured property.

1. I have done this work manually and now I want to automate using python. I have written the code for the hemisphere and filling up the hemisphere using bpy.ops.mesh.fill().

2. My problem is when I created a hemisphere using circle and bisecting it, I have extruded one edge to another with proper dimension. But there is another edge that is occurring based on code. I am unable to overcome it. I have posted the code and the image below for reference. Please check and help me out with how to delete that extra edge.

3. I want to create cell fracture using python. I have created particles using python. But I want cell fracture also in python, but since its add-on in blender, I am unable to do in Python.

Here is the code:

#Imports.
import bpy
import numpy as np
import math
from array import *
from mathutils import Vector
from math import degrees

# Draw hemisphere of 1m radius
bpy.ops.mesh.primitive_circle_add(radius=1, enter_editmode=True, align='WORLD', location=(0, 0, 0))
bpy.ops.mesh.bisect(plane_co=(0, 0, 0), plane_no=(0, -1, 0), clear_inner=True, clear_outer=False, xstart=0, xend=0, ystart=1, yend=1)

# Extrude vertices after hemisphere
bpy.ops.mesh.extrude_region_move(MESH_OT_extrude_region={"use_normal_flip":False, "mirror":False}, TRANSFORM_OT_translate={"value":(2, 0, 0), "orient_type":'GLOBAL', "orient_matrix":((1, 0, 0), (0, 1, 0), (0, 0, 1)), "orient_matrix_type":'GLOBAL', "constraint_axis":(True, False, False), "mirror":False, "use_proportional_edit":False, "proportional_edit_falloff":'SMOOTH', "proportional_size":1, "use_proportional_connected":False, "use_proportional_projected":False, "snap":False, "snap_target":'CLOSEST', "snap_point":(0, 0, 0), "snap_align":False, "snap_normal":(0, 0, 0), "gpencil_strokes":False, "cursor_transform":False, "texture_space":False, "remove_on_cancel":False, "release_confirm":False, "use_accurate":False})

# Fill
bpy.ops.mesh.select_linked(delimit=set())
bpy.ops.mesh.fill()

Hemisphere with extra edge image:

Hemisphere with particles image:

Answer 1

Fill the circle primitive.

Going by the demonstration it appears you wish to have a flat filled semi circle.

In which case recommend filling the circle when created, then ditching the extrude and fill operators.

Test script, have chosen a triangular fan fill for the circle, for an ngon, choose 'NGON'

import bpy


# Draw hemisphere of 1m radius
bpy.ops.mesh.primitive_circle_add(
    radius=1, 
    enter_editmode=True, 
    align='WORLD', 
    location=(0, 0, 0), 
    fill_type='TRIFAN',  # NOTHING  or NGON
    )
    
bpy.ops.mesh.bisect(
    plane_co=(0, 0, 0), 
    plane_no=(0, -1, 0), 
    clear_inner=True,
    )

In question code after the bisect operator the verts on bisect line are selected. The extrude move operator creates an edge for each from original vert to 2 units in x direction.