get names from names.txt get transactions from transactions.txt

display who owe what like so

The output of the program should print the following lines:

Alice pays $ xx.xx to David.

Bob pays $ xx.xx to Claire.

And so on.

names.txt

Alice Bob Claire David 

transtions.txt

Bob paid $  55.90 for petrol. Bob paid $  70 for house-cleaning. Bob paid $  85.60 for lunch. Claire paid $  100.10 for phone bill. Claire paid $  103.45 for dinner. Claire paid $  30.80 for snacks. David paid $  170.80 for groceries. David paid $  33.40 for breakfast. David paid $  63.50 for utilities. 

my code works and get the right result, just wondering if there is a cleaner way.

The code creates payment object, adds people, then adds payments, then gets liabilities.

Let me know what y’all think.

import re from decimal import Decimal  def filer(file):     f = open(file, 'r')     lines = []     for line in f.readlines():         lines.append(line.strip())     return lines  def parse_lines(lines, **kwargs):     compilers = kwargs.get('keys', ['money', 'name', 'bill'])     parses = []     for line in lines:         l1 = Parser(line, keys=compilers)         parses.append(l1.get_dict())     return parses   class Parser(object):     patterns    = {'name_pattern':'^([\w\-]+)','money_pattern':'(\d+.?\d*)','bill_pattern':"[\w'-]+\.$  "}     keys        = ['money', 'name', 'bill']      def __init__(self, line, **kwargs):         if 'patterns' in kwargs:             self.patterns.update(kwargs.get('patterns'))             del kwargs['patterns']          self.__dict__.update(kwargs)          for key in self.keys:             key_str = key+'_pattern'             parser  = re.compile(self.patterns[key_str])             value   = parser.search(line)             setattr(self, key, value.group(0))      def get_dict(self):         rtn = {}         for key in self.keys:             rtn[key] = getattr(self, key)         return rtn  class Payments(object):      def __init__(self, **kwargs):         self.people         = {}         self.formatter  = "{from} ​pays​ {currency}{amount} ​to​ {to}."         self.currency   = '$  '         self.__dict__.update(kwargs)      def add_person(self, person):         self.people[str(person.name)] = person      def add_payment(self, payment):         person = self.people[payment['name']]         person.add_to(payment)      def get_liabilities(self):         liabilities     = []         for name, person in self.people.items():             person.set_share(len(self.people.items()))          for name, person in self.people.items():             """gets share & sets it against each person in the group"""             person.set_liability(self.people, self.currency)             liabilities += person.liabilities          return liabilities      def print_liabilities(self):         liabilities = []         for liability in self.get_liabilities():             liabilities.append(self.formatter.format(**liability))         return liabilities  class Person(object):     def __init__(self, **kwargs):         self.name   = ""         self.items  = []         self.paid   = 0         self.share  = 0         self.liabilities = []         self.__dict__.update(kwargs)      def add_to(self, payment):         """ payment must have keys: 'name', 'money'"""         if payment['name'] == self.name:             self.items.append(payment)      def _get_paid(self):         balance = 0         for item in self.items:             amount  = Decimal(item['money'],2)             balance += amount         return Decimal(balance, 2)      def set_share(self, total_people):         """total amount paid is divided by the number of          people to get the liabilities of each person"""         self.paid   = self._get_paid()         self.share  = round(self.paid/Decimal(total_people), 2)      def _set_extras(self, liability, keys):         """sets extra properties"""         for key in keys:             if hasattr(self, key):                 liab_dict[key] = getattr(self, key)      def set_liability(self, people, currency):         """if owed is share is greater than owed, name needs to pay this"""         for name, person in people.items():             if self.name != name:                 """if owed is greater than what I have paid then add to liabilities"""                 diff = self.share - person.share                 if diff < 0:                     liab_dict = {'from':self.name,'to': name,'amount':-diff, 'currency':currency }                     self.liabilities.append(liab_dict)  class PaymentBuilder(object):     people  = []     def __init__(self, **kwargs):         transactions    = kwargs.get('transaction_file','./transactions.txt')         names           = kwargs.get('names_file','./names.txt')         self.payments   = Payments()         self.trans      = parse_lines(filer(transactions))         self.names      = filer(names)          for name in self.names:             self.payments.add_person(Person(name=name))         for tran in self.trans:             self.payments.add_payment(tran)      def liabilities(self):         return [ liability for liability in self.payments.print_liabilities()]