geekcomputers/Python · error · Exception
Invalid Position
Error message
Invalid Position
What it means
insert_at in the circular linked list raises a generic Exception when idx is negative or greater than the list length, i.e. the insertion position is outside the valid range [0, length]. Bounds 0 and length are handled by insert_at_beginning/insert_at_end before this check.
Source
Thrown at LinkedLists all Types/circular_linked_list.py:87
if self.head is None:
print("The List is Empty!")
return
temp = self.head.next
print(f"{self.head.data} ->", end=" ")
while temp != self.head:
print(f"{temp.data} ->", end=" ")
temp = temp.next
print(f"{self.tail.next.data}")
def insert_at(self, idx, data):
if idx == 0:
self.insert_at_beginning(data)
return
elif idx == self.length:
self.insert_at_end(data)
return
elif 0 > idx or idx > self.length:
raise Exception("Invalid Position")
return
pos = 0
temp = self.head
while temp:
if pos == idx - 1:
node = Node(data, temp.next)
temp.next = node
self.length += 1
return
pos += 1
temp = temp.next
def remove_at(self, idx):
if 0 > idx or idx >= self.length:
raise Exception("Invalid Position")
elif idx == 0:
self.pop_at_beginning()
return
View on GitHub (pinned to 40f4cd2652)
Solutions
- Validate idx against 0 <= idx <= len(list)/.length before calling insert_at
- Treat -1 from search as 'not found' and skip the insert instead of passing it through
- Prefer append/insert_at_end when adding at the tail
Example fix
# before
cll.insert_at(pos, data)
# after
if 0 <= pos <= cll.length:
cll.insert_at(pos, data)
else:
raise IndexError('position out of range') Defensive patterns
Strategy: validation
Validate before calling
def can_insert(cll, idx) -> bool:
return 0 <= idx <= cll.length Try / catch
try:
cll.insert_at(idx, data)
except Exception:
raise IndexError(f'insert position {idx} out of range') from None Prevention
- Check 0 <= idx <= length before inserting
- Never pass -1 from a failed search directly as an index
- Use length-based loops, not hardcoded positions
When it happens
Trigger: Calling insert_at(idx) with idx < 0 or idx > list.length, e.g. insert_at(10) on a 3-node list; computing an index from user input or search results that returned -1/not-found.
Common situations: Using find()/index-of returning -1 as an insert position; off-by-one when iterating positions; inserting into an empty list with idx > 0.
Related errors
AI-assisted analysis of geekcomputers/Python@40f4cd2652 (2026-08-27).
Data as JSON: /api/errors/f64a4a186774271c.
Report an issue: GitHub.