transactions.ipynb

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   "source": "'''\nSarah rents a car for the trip - she pays $400 for the car, which is used by Alice, John, \nBob and herself. Later in the trip, John went out and bought groceries for $100, \nwhich was used only by Alice and Bob.\n\nNow, the trip is over and everyone wants to get paid back what they are owed - \nprint out the list of transactions that would settle everyone's debts.\n\n\nledger = Ledger()\nledger.transaction('sarah', 400, [alice, john, bob, sarah])\nledger.transaction('john', 100, [alice, bob])\n\n'''\n\nclass Ledger():\n    def __init__(self, accounts):\n        self.accounts = []    \n        self.transactions = []\n        for a in accounts:\n            self.addAccount(a)\n            \n    def addAccount(self, account):\n        self.accounts.append(account)\n        \n    def transaction(self, payer, amount, beneficiaries):\n        self.transactions.append({'payer': payer, 'amount': amount, 'beneficiaries': beneficiaries})\n    \n    def settle(self):\n        balances = {}\n        for account in self.accounts:\n            balances[account] = 0\n            \n        for transaction in self.transactions:\n            balances[transaction['payer']] += transaction['amount']\n            \n            owed  = transaction['amount'] / len(transaction['beneficiaries'])\n            for beneficiary in transaction['beneficiaries']:\n                if beneficiary != transaction['payer']:\n                    print(\"{} owes {} ${:.2f}\".format(beneficiary, transaction['payer'], owed))\n            \n            \n        \n            \n        \n        \nledger = Ledger(['alice', 'john', 'bob', 'sarah'])\nledger.transaction('sarah', 400, ['alice', 'john', 'bob', 'sarah'])\n\nledger.transaction('john', 100, ['alice', 'bob'])\nledger.settle()\n        \n\n\n\n\n\n\n",
   "execution_count": 9,
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": "alice owes sarah $100.00\njohn owes sarah $100.00\nbob owes sarah $100.00\nalice owes john $50.00\nbob owes john $50.00\n"
    }
   ]
  },
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   "cell_type": "code",
   "source": "",
   "execution_count": null,
   "outputs": []
  }
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