WebLog.py

# DailyCoding
##
##We use a Linked Data Structure

class Node:
    '''Node Object'''

    def __init__(self, val, nextVal):
        self.val = val
        self.nextVal = nextVal


class LinkedList:
    """Simple LinkedList Data Structure"""

    def __init__(self):
        self.previous, self.current = None, None  # instantiate current and previous Nodes
        self.head, self.tail = None, None  ##instantiate head and tail as null Values

    def add(self, val):
        """Add val to List"""
        if self.head == None:  # if linked List is empty
            self.previous = Node(val, self.tail)  # append first element in list
            self.current = self.previous  # set current equal to first element; previous
            self.head = Node(None, self.previous)  # redefine Val of Head Variable to reference previous Node
        ##Otherwise if list is not empty
        elif self.current.nextVal == self.tail:
            self.current.nextVal = Node(val, self.tail)  # add new value to end of Linked DataSet
        else:  ##else, update the value of current to the last nonempty Node
            while self.current.nextVal != self.tail: self.current = self.current.nextVal
            self.current.nextVal = Node(val, self.tail)  ##append new val to end of list

    def isEmpty(self):
        """Evaluate if List is Empty or Not"""
        if self.head is None: return True
        return False

    def get(self, ith_val):
        """Return ith val in list"""
        if self.isEmpty(): return None  # return None Object if list is Empty
        self.current, ithVal = self.previous, 1  ##set current to first value in list. So ithVal is at 1
        while ithVal != ith_val:
            self.current = self.current.nextVal
            ithVal += 1
        return self.current.val


class WebLog:
    """Log for Web order"""

    def __init__(self):
        self.__log = LinkedList()  # instantiate the log dataSet

    def record(self, order_id):
        '''add order id to log'''
        self.__log.add(order_id)

    def get_Last(self, ithOrder):
        """return the ith order in List"""
        return self.__log.get(ithOrder)


# ###Test
# orders = WebLog()
# for num in range(10,21): orders.record(num)
# print(orders.get_Last(4))
# print(orders.get_Last(10))

#################################################################################################################
"""This could be simply implemented with a List"""


class WebLog2:
    def __init__(self):
        self.log = []  ##instantiate list to record data

    def record(self, order_id):
        self.log.append(order_id)

    def get_last(self, ithOrder):
        return self.log[ithOrder]


###Test WebLog2
logData = WebLog2
for n in range(50, 101):
    logData.record(n)

print(logData.get_last(4))
print(logData.get_last(8))
print(logData.get_last(3))