Files
street_group_tech_test/analyse_properties/__init__.py

121 lines
3.4 KiB
Python

"""
Daniel Tomlinson (dtomlinson@panaetius.co.uk).
Technical test for Street Group.
"""
import csv
import hashlib
import io
from importlib import resources
from itertools import chain, islice
import apache_beam as beam
from apache_beam.io import fileio
from analyse_properties.debug import DebugShowEmptyColumn, DebugShowColumnWithValueIn
def csv_reader(csv_file):
return csv.reader(io.TextIOWrapper(csv_file.open()))
def slice_by_range(element, *ranges):
return chain(*(islice(element, *r) for r in ranges))
class DropRecordsSingleEmptyColumn(beam.DoFn):
def __init__(self, index):
self.index = index
def process(self, element):
column = element[self.index]
if len(column) == 0:
return None
yield element
class DropRecordsTwoEmptyColumn(beam.DoFn):
def __init__(self, index_0, index_1):
self.index_0 = index_0
self.index_1 = index_1
def process(self, element):
column_0 = element[self.index_0]
column_1 = element[self.index_1]
if len(column_0) == 0 and len(column_1) == 0:
return None
yield element
class SplitColumn(beam.DoFn):
def __init__(self, index, split_char):
self.index = index
self.split_char = split_char
def process(self, element):
try:
part_0, part_1 = element[self.index].split(self.split_char)
element[self.index] = part_1.strip()
element.append(part_0.strip())
yield element
except ValueError:
element.append("")
yield element
class GenerateUniqueID(beam.DoFn):
def process(self, element):
unique_string = ",".join(element[2:])
hashed_string = hashlib.md5(unique_string.encode())
element.append(hashed_string.hexdigest())
yield element
def main():
csv_data = resources.path(
"analyse_properties.data", "pp-monthly-update-new-version.csv"
# "analyse_properties.data", "pp-complete.csv"
)
with beam.Pipeline() as pipeline:
# Load the data
with csv_data as csv_data_file:
# https://github.com/apache/beam/blob/v2.32.0/sdks/python/apache_beam/io/fileio_test.py#L155-L170
load = (
pipeline
| fileio.MatchFiles(str(csv_data_file))
| fileio.ReadMatches()
| beam.FlatMap(csv_reader)
)
# Clean the data
clean = (
load
| "Drop unneeded columns"
>> beam.Map(lambda element: list(slice_by_range(element, (1, 4), (7, 14))))
| "Convert to Upper Case"
>> beam.Map(lambda element: [e.upper() for e in element])
| "Strip leading/trailing whitespace"
>> beam.Map(lambda element: [e.strip() for e in element])
| "Drop Empty Postcodes"
>> beam.ParDo(DropRecordsSingleEmptyColumn(2))
| "Drop empty PAON if missing SAON"
>> beam.ParDo(DropRecordsTwoEmptyColumn(3, 4))
# | beam.ParDo(DebugShowColumnWithValueIn(3, ","))
| beam.ParDo(DebugShowColumnWithValueIn(2, "AL1 4SZ"))
| beam.ParDo(SplitColumn(3, ","))
# | beam.Map(print)
)
# Prepare the data
prepare = (
clean
| beam.ParDo(GenerateUniqueID())
| beam.Map(print)
)
if __name__ == "__main__":
main()