python - 有没有办法按值删除列表中的对象？

Question

“list.remove”函数不按值比较对象

假设代码是：

class item:
def __init__(self, a, b):
    self.feild1 = a
    self.field2 = b

a = item(1,4)
b = item(1,4)
l = [a]
l.remove(b) # doesn't remove l[0]

标签： pythonpython-3.x

Answer 1

因为您不提供__eq__实现，所以您的类从object. object.__eq__不比较属性的值，它只是检查以查看id(a) == id(b). 您需要编写自己的__eq__：

class item:
    def __init__(self, a, b):
        self.field1 = a
        self.field2 = b
    def __eq__(self, other):
        if not isinstance(other, item):
            return NotImplemented
        return self.field1 == other.field1 and self.field2 == other.field2

a = item(1,4)
b = item(1,4)
l = [a]
l.remove(b)

print(l)
# []