I have a custom class in Python where I define __lt__ so that objects can be compared.
But when I try to sort a list of these objects, the ordering doesn’t follow my comparison logic.
Here is a minimal reproducible example:
class Item:
def __init__(self, value):
self.value = value
def __lt__(self, other):
print("Comparing", self.value, "and", other.value)
return self.value > other.value # reverse sorting
items = [Item(1), Item(3), Item(2)]
sorted_items = sorted(items)
print([i.value for i in sorted_items])
Output:
[1, 2, 3]
This is ascending order, but my __lt__ should have reversed it.
Why is Python ignoring my custom comparison method, and how can I make it respect it?