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pythonobjectsortedlist

Insert a custom object in a sorted list

I implemented an object with a numerical attribute. I want to keep a list of those objects sorted according to that attribute, without need to run a sort method at each insertion. I took a look to bisect module, but I do not know if I can use it also with an object. What is the best way to do that?

Solution

  • You can do this for your custom object if you implement the __lt__ method, because this is what bisect will use to compare your object.

    >>> class Foo(object):
...     def __init__(self, val):
...         self.prop = val # The value to compare
...     def __lt__(self, other):
...         return self.prop < other.prop
...     def __repr__(self):
...         return 'Foo({})'.format(self.prop)
...
>>> sorted_foos = sorted([Foo(7), Foo(1), Foo(3), Foo(9)])
>>> sorted_foos
[Foo(1), Foo(3), Foo(7), Foo(9)]
>>> bisect.insort_left(sorted_foos, Foo(2))
>>> sorted_foos
[Foo(1), Foo(2), Foo(3), Foo(7), Foo(9)]