CODEWITHSUNDEEP
pythondata-structures
Prathamesh Sawant
Prathamesh Sawant

Reputation: 137

How to format the output print statement to print linked list?

So I trying to print the linked list after the string but I not able to do it. The print statement is in pop function inside unordered class

The linked list always get printed first and then the string i.e

54 26 56 93 17 77 31 7
Original Linked List: None

My Desired Output

Original Linked List: 54 26 56 93 17 77 31 7

class Node:
    def __init__(self, initdata):
        self.data = initdata
        self.next = None

    def getData(self):
        return self.data

    def getNext(self):
        return self.next

    def setData(self,newdata):
        self.data = newdata

    def setNext(self,newnext):
        self.next = newnext

class UnorderedList:

    def __init__(self):
        self.head = None

    def isEmpty(self):
        return self.head == None

    def printList(self):
        temp = self.head
        while (temp):
            print(temp.data, end=" ")
            temp = temp.next
        print('\n')

    def pop(self):
        print('Original Linked List:' self.printList())
        current = self.head
        previous = None
        while current.getNext() != None:
            previous = current
            current = current.getNext()
        previous.setNext(current.getNext())
        print('New linked list after pop is:', self.printList())

So I have tried formatting it with

print(f'Orginal Linked List: {self.printList()})
print('Original Linked List: %d' %(self.printList()))

Nothing really works I am new to programming I appreciate your help.

Upvotes: 0

Views: 112

Answers (1)

Samwise
Samwise

Reputation: 71464

You need a function that returns a list rather than printing a list. It's easiest if you name this function __str__ because then it'll get called automatically whenever anything tries to convert your list to a string.

Change:

    def printList(self):
        temp = self.head
        while (temp):
            print(temp.data, end=" ")
            temp = temp.next
        print('\n')

to:

    def __str__(self):
        s = ''
        temp = self.head
        while temp:
            s += str(temp.data) + " "
            temp = temp.next
        return s[:-1]

and then you can do:

print(f'Original Linked List: {self})

which will automatically call your __str__ method and put the result into the f-string.

Upvotes: 1

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