对类实例列表进行排序 Python
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Sort a list of Class Instances Python
提问by
I have a list of class instances -
我有一个类实例列表 -
x = [<iteminstance1>,...]
among other attributes the class has scoreattribute. How can I sort the items in ascending order based on this parameter?
在其他属性中，该类具有score属性。如何根据此参数按升序对项目进行排序？
EDIT: The listin python has something called sort. Could I use this here? How do I direct this function to use my scoreattribute?
编辑：list在 python 中有一个叫做sort. 我可以在这里使用这个吗？如何指示此函数使用我的score属性？
采纳答案by Ned Batchelder
import operator
sorted_x = sorted(x, key=operator.attrgetter('score'))
if you want to sort x in-place, you can also:
如果您想就地对 x 进行排序，您还可以：
x.sort(key=operator.attrgetter('score'))
回答by kindall
In addition to the solution you accepted, you could also implement the special __lt__()("less than") method on the class. The sort()method (and the sorted()function) will then be able to compare the objects, and thereby sort them. This works best when you will only ever sort them on this attribute, however.
除了您接受的解决方案之外，您还可以__lt__()在类上实现特殊（“小于”）方法。然后该sort()方法（和sorted()函数）将能够比较对象，从而对它们进行排序。但是，当您仅根据此属性对它们进行排序时，此方法效果最佳。
class Foo(object):
def __init__(self, score):
self.score = score
def __lt__(self, other):
return self.score < other.score
l = [Foo(3), Foo(1), Foo(2)]
l.sort()
