Creating separate list of x and y coordinates from array after using getPart?

Question

I have an array of points by using getPart on each of the four polygons in the shapefile. I am trying to figure out a way to create a list of x and y coordinates in my for loop and name them xCoords and yCoords so I can plug them into my functions to calculate the perimeter. For some reason, I can't seem to make a list that separates the x and y points... any ideas?

Note: When I print point.X or point.Y, it gives me one coordinate. I know that I have to write some code in my for loop to get separate lists of x and y coordinates for each polygon, I'm just not sure how to.

import arcpy, os
from arcpy import env
from arcpy.sa import *
from math import *


env.workspace = r"H:\GEOG 4303\cho_lab4\lab4\data"
env.overwriteOutput = 1

theme = 'watersheds_3D.shp'
DEM = 'demlab4'

cursor = arcpy.da.SearchCursor(theme, ["SHAPE@", "Id"])
for row in cursor:
    array = arcpy.Array()
    print("Polygon Id: {0}".format(row[1]))
    for Id in row[0].getPart():
        print("Polygon coordinates: {0}".format(Id.count))
        for point in Id:
            print("X: {0}, Y: {1}".format(point.X, point.Y))
            array.add(arcpy.Point(point.X, point.Y))
        print array

Answer 1

A bit unclear what you want but you should be able to use collections.defaultdict:

Using list as the default_factory, it is easy to group a sequence of key-value pairs into a dictionary of lists

import arcpy
from collections import defaultdict
fc = r"C:\folder\shapefile.shp"
dx = defaultdict(list)
dy = defaultdict(list)

with arcpy.da.SearchCursor(fc,['OID@','SHAPE@']) as cursor:
    for row in cursor:
        array1=row[1].getPart()
        for vertice in range(row[1].pointCount):
            pnt=array1.getObject(0).getObject(vertice)
            dx[row[0]].append(pnt.X)
            dy[row[0]].append(pnt.Y)

You will now have two dictionaries with ObjectID as key and a list of coordinates for each polygon as values . For example all the vertices for the first polygon (objectid 0) as lists:

print(dx[0])
print(dy[0])
>>[800000.0, 800000.0, 700000.0, 700000.0, 800000.0]
>>[7400000.0, 7300000.0, 7300000.0, 7400000.0, 7400000.0]

Start and end coordinates are the same. Can be removed if you want.

Iterating:

for oid in dx:
    print(dx[oid], dy[oid])
>>[800000.0, 800000.0, 700000.0, 700000.0, 800000.0] [7400000.0, 7300000.0, 7300000.0, 7400000.0, 7400000.0]
>>[800000.0, 800000.0, 700000.0, 700000.0, 800000.0] [7400000.0, 7300000.0, 7300000.0, 7400000.0, 7400000.0]
>>...