I have created a list of instances (with a for loop). When I try to delete single instances from this list I get an error saying they aren't in the list. I have made a simple example showing my problem:
class example ():
list = []
def __init__ (self, name):
example.list.append(self)
self.name = name
for i in range(5):
name = ("example_" + str(i+1))
name = example(name)
to_delete = []
to_delete.append(example.list[2])
to_delete.append(example.list[0])
to_delete.append(example.list[4])
for j in to_delete:
example.list.remove(to_delete)
print(example.list)
The objects to delete are in the list. At least, when I print them out:
List of instances:
[<__main__.example object at 0x7fdc77082c50>, <__main__.example object at 0x7fdc77082be0>, <__main__.example object at 0x7fdc77082c88>, <__main__.example object at 0x7fdc77082b00>, <__main__.example object at 0x7fdc77082b38>]
Objects to remove:
[<__main__.example object at 0x7fdc77082c88>, <__main__.example object at 0x7fdc77082c50>, <__main__.example object at 0x7fdc77082b38>]
Why is this behaving oddly?
You are trying to remove the whole list to_delete from the list, not each item individually. As the object to_delete itself is not in the list (though each item it contains is), it will throw an error.
This:
for j in to_delete:
example.list.remove(to_delete) #try to remove object to_delete
Should be:
for j in to_delete:
example.list.remove(j) #try to remove each object IN to_delete
Additionally, you could simply use list comprehension to do this:
example.list = [x for x in example.list if x not in to_delete]