您想要的就是所谓的拓扑排序。尽管可以使用内建函数实现sort()，但是这很尴尬，最好直接在python中实现拓扑排序。
为什么会很尴尬？如果您在Wiki页面上研究这两种算法，它们都依赖于运行中的一组“标记节点”，很难sort()使用这种概念来扭曲形式，因为key=xxx（甚至cmp=xxx）最适合与无状态比较函数一起使用，尤其是因为timsort不保证该元素将被检查的顺序。我（美丽的）肯定，任何解决方案确实 使用sort()将要结束了冗余计算每个呼叫键/ CMP功能的一些信息，以避开无国籍问题。
以下是我一直在使用的算法（对一些JavaScript库依赖关系进行排序）：
def topological_sort(source):
"""perform topo sort on elements.
:arg source: list of ``(name, [list of dependancies])`` pairs
:returns: list of names, with dependancies listed first
"""
pending = [(name, set(deps)) for name, deps in source] # copy deps so we can modify set in-place
emitted = []
while pending:
next_pending = []
next_emitted = []
for entry in pending:
name, deps = entry
deps.difference_update(emitted) # remove deps we emitted last pass
if deps: # still has deps? recheck during next pass
next_pending.append(entry)
else: # no more deps? time to emit
yield name
emitted.append(name) # <-- not required, but helps preserve original ordering
next_emitted.append(name) # remember what we emitted for difference_update() in next pass
if not next_emitted: # all entries have unmet deps, one of two things is wrong...
raise ValueError("cyclic or missing dependancy detected: %r" % (next_pending,))
pending = next_pending
emitted = next_emitted
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