Hi Greg,
Try this (next time try solving yourself first and post what you've
done and specific problems you're having trouble with.):
import csv
# read data using csv reader...
fileobj = open('text_data.txt')
csvreader = csv.reader(fileobj, delimiter=';')
csvreader.next() # skip header
# store lines indexed by line id in dict called polylines
# lines themselves are represented by lists.
polylines = {}
# store polygons made up of lines in dict called polygons
polygons = {}
# loop through point data from csvreader and unpack into
# dicts/lists
for line in csvreader:
#unpack lineid and polyid
lineid = line[3]
polyid = line[4]
# get the point data as list by slicing
# first entry in list is point id.
# maybe make points into a dict as well?
point = line[0:3]
# store the point in the correct line list:
# first create an empty list if needed then append
polylines[lineid] = polylines.get(lineid, [])
polylines[lineid].append(point)
# store the line in the correct polygon dict:
# first create empty dict if needed then add
# if the line not already part of the polygon.
polygons[polyid] = polygons.get(polyid, {})
if not lineid in polygons[polyid]:
polygons[polyid][lineid] = polylines[lineid]
# check the results with some pretty printing:
import pprint
pp = pprint.PrettyPrinter(indent=4)
print "lines read from csv file:"
pp.pprint(polylines)
print "polygons read from csv file:"
pp.pprint(polygons)
Walter
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