Question

PYTHON. Continues off another code. I don't understand this. Someone please help! Comment the lines please so I can understand

LinkedList ADT:

class myLinkedList:
    def __init__(self):
        self.__head = None
        self.__tail = None
        self.__size = 0

    def insert(self, i, data):
        if self.isEmpty():
            self.__head = listNode(data)
            self.__tail = self.__head
        elif i <= 0:
            self.__head = listNode(data, self.__head)
        elif i >= self.__size:
            self.__tail.setNext(listNode(data))
            self.__tail = self.__tail.getNext()
        else:
            current = self.__getIthNode(i - 1)
            current.setNext(listNode(data, current.getNext()))
            if current == self.__tail:
                self.__tail = self.__tail.getNext()
        self.__size += 1

    def __getIthNode(self, i):
        current = self.__head
        count = 0
        while current is not None and count < i:
            count = count + 1
            current = current.getNext()
        return current

    def __str__(self):
        current = self.__head
        result = ""
        while current is not None:
            result = result + " " + str(current.getData())
            current = current.getNext()
        return result

    #returns True if list is empty, else False
    def isEmpty(self):
        return self.__head==None

    #returns the length
    def __len__(self):
        '''count = 0
        current=self.__head
        #counting number of nodes
        while current is not None:
            count = count + 1
            current = current.getNext()
        #returning count
        return count'''
        return self.__size

    #adds to the front
    def prepend(self, item):
        #adding the item at index 0
        self.insert(0,item)

    #adds to the rear
    def append(self,item):
        #adding the item at the end
        self.insert(len(self),item)

    #removes and returns the element at index i
    def pop(self, i):
        #validating index
        if i<0 or i>=len(self):
            return None #invalid index
        #finding ith node
        node=self.__getIthNode(i)
        #if it is head, updating head node
        if node==self.__head:
            self.__head=self.__head.getNext()
            self.__size-=1
            return node.getData() #returning removed data
        #finding previous node
        prev=self.__getIthNode(i-1)
        #linking node at i+1 as next node of node at i-1
        prev.setNext(node.getNext())
        self.__size -= 1
        return node.getData() #returning removed data

    #helps to access data by index (using [])
    def __getitem__(self, index):
        #returning data of node at index
        return self.__getIthNode(index).getData()

    #helps to set data by index (using [])
    def __setitem__(self, index, value):
        #updates the data of node at index
        self.__getIthNode(index).setData(value)

    #returns the index of an item, if exists
    def find(self,item):
        #looping and comparing each item with target
        for i in range(len(self)):
            if self.__getitem__(i)==item:
                #found
                return i
        return -1 #not found

student class ADT:

class Student:
def __init__(self, id=None, name=""):
self.id = id
self.name = name

def getID(self):
return self.id

def getName(self):
return self.name

def setID(self, id):
self.id = id

def setName(self, name):
self.name = name

def __str__(self):
#print out
print(str(self.id) + "(" + self.name+")")

def __cmp__(self,other_id):
ot_id = other_id.getID()
if (self.id < ot_id):
p = -1
elif (self.id > ot_id):
p = 1
elif (self.id == ot_id):
p = 0
return p

def __eq__(self,other_id):
x = self.__cmp__(other_id)
if x == 0:
print(True)
else:
print(False)

def __ne__(self,other_id):
x = self.__cmp__(other_id)
if x == 0:
print(False)
else:
print(True)

def __lt__(self,other_id):
x = self.__cmp__(other_id)
if x == -1:
print(True)
else:
print(False)

def __le__(self,other_id):
x = self.__cmp__(other_id)
if x == 0 or x==-1:
print(True)
else:
print(False)

def __gt__(self,other_id):
k = self.__cmp__(other_id)
if (k == 1):
print(True)
else:
print(False)

def __ge__(self,other_id):
k = self.__cmp__(other_id)
if (k == 0 or k==1):
print(True)
else:

print(False)

LinkedList ADT to store student records(code is below). Using LinkedList ADT instead of the Python List. You will need to use the Student ADT(code is below)

1. Imports the Student class
2. Imports the time module
3. Imports the myLinkedList class

1. Create a main() function which:
   1. Open the list of names files and read the student information and puts them into a list of Student's. You will need to use the strip() function on the line of input from the file to remove extra white space, then use split() using a tab as a deliminator to split the line of input into the student ID and name. The ID should also be converted to an integer so that it can more easily be compared with other IDs.
   2. Close the 1st file
   3. Open the search file and read each line of the 2nd file and create a new Student record (except that it will have only an ID and not a name). Search for a match in the list of Student's and print the record that matches. If there is no match, then print an appropriate message. You created a function the the myLinkedList class that should help with this.
   4. An sample output might looks something like this:
      
      Found student record: 7654321 (Ashley Tomkin)
      Found student record: 2345678 (Katie Smith)
      Student ID: 1234567 not found
      Found student record: 3456789 (Matt Simpson)
      Student ID 9876543 not found
      
2. You should first work with the short versions of the input file before moving on to the medium versions. After your program is successfully capable to adding all of the students to the Linked List and is able to read the student IDs in the search file and print an appropriate message, then you want to time how long it takes.  
   1. First, comment out the printing of the messages, so that you aren't timing that.  
   2. Surround the section of code you want to time with two time stamps (calls to the time.time() method. The elapse time can be calculated by taking the difference between the two time stamps. For example:
           startTime = time.time()
           # Do the stuff you want to time
      
           endTime = time.time()
           print("Time to do <whatever> " + format(endTime - startTime, "6.4f") + " seconds.")
      
   1. Time how long it takes to insert the student records into the Linked List as well as search for them using the medium versions of the files. For example, you might something like this:
      
      The time to insert 10000 student records into a Linked List = 0.0341 seconds.
      The time to search 10000 student records from a Linked List = 23.9849 seconds.

Answer 1

here is the answer ............

class myLinkedList: #this is for the creation of linked list..
    def __init__(self):
        self.__head = None
        self.__tail = None
        self.__size = 0

    def insert(self, i, data): #this function is used for the inserting the data in the linked list...
        if self.isEmpty():
            self.__head = listNode(data)
            self.__tail = self.__head
        elif i <= 0:
            self.__head = listNode(data, self.__head)
        elif i >= self.__size:
            self.__tail.setNext(listNode(data))
            self.__tail = self.__tail.getNext()
        else:
            current = self.__getIthNode(i - 1)
            current.setNext(listNode(data, current.getNext()))
            if current == self.__tail:
                self.__tail = self.__tail.getNext()
        self.__size += 1

    def __getIthNode(self, i): #this is for the getting requested node..
        current = self.__head
        count = 0
        while current is not None and count < i:
            count = count + 1
            current = current.getNext()
        return current

    def __str__(self): #this is for the current head node
        current = self.__head
        result = ""
        while current is not None:
            result = result + " " + str(current.getData())
            current = current.getNext()
        return result

    #returns True if list is empty, else False
    def isEmpty(self):
        return self.__head==None

    #returns the length
    def __len__(self):
        '''count = 0
        current=self.__head
        #counting number of nodes
        while current is not None:
            count = count + 1
            current = current.getNext()
        #returning count
        return count'''
        return self.__size

    #adds to the front
    def prepend(self, item):
        #adding the item at index 0
        self.insert(0,item)

    #adds to the rear
    def append(self,item):
        #adding the item at the end
        self.insert(len(self),item)

    #removes and returns the element at index i
    def pop(self, i):
        #validating index
        if i<0 or i>=len(self):
            return None #invalid index
        #finding ith node
        node=self.__getIthNode(i)
        #if it is head, updating head node
        if node==self.__head:
            self.__head=self.__head.getNext()
            self.__size-=1
            return node.getData() #returning removed data
        #finding previous node
        prev=self.__getIthNode(i-1)
        #linking node at i+1 as next node of node at i-1
        prev.setNext(node.getNext())
        self.__size -= 1
        return node.getData() #returning removed data

    #helps to access data by index (using [])
    def __getitem__(self, index):
        #returning data of node at index
        return self.__getIthNode(index).getData()

    #helps to set data by index (using [])
    def __setitem__(self, index, value):
        #updates the data of node at index
        self.__getIthNode(index).setData(value)

    #returns the index of an item, if exists
    def find(self,item):
        #looping and comparing each item with target
        for i in range(len(self)):
            if self.__getitem__(i)==item:
                #found
                return i
        return -1 #not found

student class ADT:

class Student:
def __init__(self, id=None, name=""):
self.id = id
self.name = name

def getID(self):
return self.id

def getName(self):
return self.name

def setID(self, id):
self.id = id

def setName(self, name):
self.name = name

def __str__(self):
#print out
print(str(self.id) + "(" + self.name+")")

def __cmp__(self,other_id):
ot_id = other_id.getID()
if (self.id < ot_id):
p = -1
elif (self.id > ot_id):
p = 1
elif (self.id == ot_id):
p = 0
return p

def __eq__(self,other_id):
x = self.__cmp__(other_id)
if x == 0:
print(True)
else:
print(False)

def __ne__(self,other_id):
x = self.__cmp__(other_id)
if x == 0:
print(False)
else:
print(True)

def __lt__(self,other_id):
x = self.__cmp__(other_id)
if x == -1:
print(True)
else:
print(False)

def __le__(self,other_id):
x = self.__cmp__(other_id)
if x == 0 or x==-1:
print(True)
else:
print(False)

def __gt__(self,other_id):
k = self.__cmp__(other_id)
if (k == 1):
print(True)
else:
print(False)

def __ge__(self,other_id):
k = self.__cmp__(other_id)
if (k == 0 or k==1):
print(True)
else:

print(False)