I am giving passing the argument into function still it gives error code missing argument while adding linked list

Question

I am very beginner in coding, can you help me understand the error

I am giving the parameter still the error says required 1 positional argument

Input(l1 and l2 are linked list)

l1=[2,4,3]
l2=[5,4,6]

Code

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, val=0, next=None):
#         self.val = val
#         self.next = next
class Solution:
    def inttolist(self, i) -> ListNode:
        while(i%10!=0):
            self = ListNode(i%10, inttolist(int(i/10)))
        return self
    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
        a,b,c,d=l1,l2,1,0
        while(a!=None):
            d=d+(a.val+b.val)*c
            a,b=a.next,b.next
            c=c*10
        print(d)
        self = Solution.inttolist(int(d))
        return self

Error code

TypeError: inttolist() missing 1 required positional argument: 'i'
    self = Solution.inttolist(int(d))
Line 18 in addTwoNumbers (Solution.py)
    ret = Solution().addTwoNumbers(param_1, param_2)
Line 45 in _driver (Solution.py)
    _driver()
Line 56 in <module> (Solution.py)

Answer 1

The problem is the misuse of the self variable. the self argument is a variable containing the instantiated Solution class. There are two problems with that:

1. This means that: Solution.inttolist(int(d)) , should be called using:

• self.inttolist(int(d)) .

2. You should not directly assign to the self value, create a new variable for that instead, so we have to change this:

• self = ListNode(i%10, inttolist(int(i/10))) .

Below I added a working solution, in case you are still stuck after applying the above changes.

Input

The input asks for a ListNode, so I converted your input list to their specifications using:

class ListNode:
    def __init__(self, val=0, next=None):
        self.val = val
        self.next = next

    def generate_link_list(l1: list):
        nodes = []
        for val in l1:
         

def generate_link_list(l1: list):
    nodes = []
    for val in l1:
        nodes.append(ListNode(val))

    for index, node in enumerate(nodes[:-1]):
        node.next = nodes[index + 1]
    return nodes[0]

l1 = generate_link_list(l1)
l2 = generate_link_list(l2)

Solution

With the above changes the code will become:

class Solution:
    def inttolist(self, i) -> ListNode:
        ans = 0  # <--- the new variable, instead of `self`
        while (i % 10 != 0):
            ans = ListNode(i % 10, self.inttolist(int(i / 10)))
        return ans

    def addTwoNumbers(self, l1: ListNode, l2: ListNode) -> ListNode:
        a, b, c, d = l1, l2, 1, 0
        while (a != None):
            d = d + (a.val + b.val) * c
            a, b = a.next, b.next
            c = c * 10
        print(d)
        ans = self.inttolist(int(d))
        return ans

Running:

print(Solution().addTwoNumbers(l1, l2))

Will result in the answer: 987 , which is the sum of the two lists, when you reverse their values and concatenate them.