Get the total spent from an exported CSV on Presto (prestocard.ca)

presto_fare_total.py

#!/usr/bin/env python3

import csv, sys, re
from functools import reduce

"""
From StackOverflow: https://stackoverflow.com/a/32486472

Strips whitespace off from the headers of CSV field names.
"""
class DictReaderStrip(csv.DictReader):
    @property
    def fieldnames(self):
        if self._fieldnames is None:
            # Initialize self._fieldnames
            # Note: DictReader is an old-style class, so can't use super()
            csv.DictReader.fieldnames.fget(self)
            if self._fieldnames is not None:
                self._fieldnames = [name.strip() for name in self._fieldnames]
        return self._fieldnames

def extract_value(s):
    return float(re.search(r'([£\$€])(\d+(?:\.\d{2})?)'
        , s).groups()[1])

"""
Main
"""

print('File: ' + sys.argv[1])

with open(sys.argv[1], 'r') as csvfile:
    print(reduce( # Add them up and print!
        lambda acc, x: acc + x,
        map( # Take only the amount values
            lambda x: extract_value(x['Amount']),
            filter( # Filter out top-ups
                lambda x: x['Type'] != 'Load Amount',
                DictReaderStrip(csvfile)
                )
            )
        ))