[Tutor] Problems with pytz module

[Mats Wichmann]

> On 19/07/17 20:58, Daniel Bosah wrote:

don't see a lot of benefit to using pytz here... just my opinion.  the
question does give a chance to annotate the example with some thoughts,
though; take them for what they're worth.

import datetime
import pytz

class Account:
    """Simple account class with balance"""
    # 1. if you set up balance param with a default value, you can skip
    #    the argument if account is created with no balance
    #def __init__(self, name, balance):
    def __init__(self, name, balance=0):
        self.name = name
        self.balance = balance
        self.transaction_list = []
        # 2. seems to make sense to report initial balance
        #print "Account created for " + self.name
        print "Account created for " + self.name + ", initial balance" +
balance

    def deposit(self,amount):
        # 3. to avoid cascading indents, bail on "not applicable",
        #    rather than indenting a whole function behind "applicable"
        #if amount > 0:
        if amount <= 0:
            # 4. do you want to indicate this call was a problem somehow?
            return

        self.balance += amount
        # 5. it is not very interesting to just dump a balance.
        #    Either add indication it's a deposit/withdrawal and amount,
        #    or just omit, leaving caller to print balance if they want.
        #self.show_balance()
        # 6. the pytz part is just adding confusion. In the log, store the
        #    utc time.
        # 7. suggest put the simpler/more important value first in the
log entry

#self.transaction_list.append((pytz.utc.localize(datetime.datetime.utcnow()),
amount))
        # appends traction details to list
        self.transaction_list.append((amount, datetime.datetime.utcnow()))

    def withdrawl(self, amount):
        if 0 < amount <= self.balance:
            self.balance -= amount
        else:
            print "The account must be greater then zero and no more
then your account balance"
        #self.show_balance()
        # 8. record a transaction on withdraw as well. Make it negative
        #    as show_transactions method triggers on that.
        self.transaction_list.append((-amount, datetime.datetime.utcnow()))

    def show_balance(self):
        print "Balance is {}".format(self.balance)

    def show_transactions(self):
        # 9. Presumably translog print is rare, let's say what we're doing
        print "Transaction log:"
        # after note #7, unpack in other order
        #for date, amount in self.transaction_list:
        for amount, date in self.transaction_list:
            if amount > 0:
                tran_type = "deposited"
            else:
                tran_type = "withdrawn"
                amount *= -1 # to show negative number
            # 10. Assuming you wanted to print in either case, change indent
            #     print "{:6} {} on {} (local time was
{})".format(amount, tran_type, date, date.astimezone())
            print "{:6} {} on {} UTC".format(amount, tran_type, date)
            # can add timezone-relative display back in if you wish

if __name__ == '__main__':
    # after note #1, can leave out a zero initial balance
    #tim = Account("Tim", 0)
    tim = Account("Tim")
    tim.show_balance()


    tim.deposit(1000)
    tim.show_balance()
    tim.withdrawl(500)
    tim.show_transactions()

    tim.show_balance()