我有一个复杂的Python数据结构(如果它很重要,它是一个很大的music21 score对象),由于在对象结构内部某处存在弱化,它不会发痒.我以前用堆栈跟踪和python调试器调试过这样的问题,但总是很痛苦.是否有一个工具以递归方式对对象的所有属性运行dir(),查找隐藏在列表,元组,dicts等中的对象,并返回与特定值匹配的那些(lambda函数或类似的东西).一个很大的问题是递归引用,因此需要某种备忘录函数(如copy.deepcopy使用).我试过了：
import weakrefdef findWeakRef(streamObj,memo=None):weakRefList = []if memo is None:memo = {}for x in dir(streamObj):xValue = getattr(streamObj,x)if id(xValue) in memo:continueelse:memo[id(xValue)] = Trueif type(xValue) is weakref.ref:weakRefList.append(x,xValue,streamObj)if hasattr(xValue,"__iter__"):for i in xValue:if id(i) in memo:passelse:memo[id(i)] = TrueweakRefList.extend(findWeakRef(i),memo)else:weakRefList.extend(findWeakRef(xValue),memo)return weakRefList
我可能会继续插入这个漏洞(例如,它不是我想要的替代词),但在我投入更多时间之前,想知道是否有人知道更简单的答案.它可能是一个非常有用的通用工具.
最佳答案
这似乎是答案的开始.我不得不从Python 3.2 inspect.getattr_static向后移植一些项目以使其工作,因此它不会调用仅生成新对象的属性.这是我提出的代码：
#-------------------------------------------------------------------------------# Name: treeYield.py# Purpose: traverse a complex datastructure and yield elements# that fit a given criteria## Authors: Michael Scott Cuthbert## Copyright: Copyright © 2012 Michael Scott Cuthbert# License: CC-BY#-------------------------------------------------------------------------------import typesclass TreeYielder(object):def __init__(self,yieldValue = None):'''`yieldValue` should be a lambda function thatreturns True/False or a function/method call thatwill be passed the value of a current attribute'''self.currentStack = []self.yieldValue = yieldValueself.stackVals = []t = typesself.nonIterables = [t.IntType,t.StringType,t.UnicodeType,t.LongType,t.FloatType,t.NoneType,t.BooleanType]def run(self,obj,memo = None):'''traverse all attributes of an object lookingfor subObjects that meet a certain criteria.yield them.`memo` is a dictionary to keep track of objectsthat have already been seenThe original object is added to the memo andalso checked for yieldValue'''if memo is None:memo = {}self.memo = memoif id(obj) in self.memo:self.memo[id(obj)] += 1returnelse:self.memo[id(obj)] = 1if self.yieldValue(obj) is True:yield obj### now check for sub values...self.currentStack.append(obj)tObj = type(obj)if tObj in self.nonIterables:passelif tObj == types.DictType:for keyX in obj:dictTuple = ('dict',keyX)self.stackVals.append(dictTuple)x = obj[keyX]for z in self.run(x,memo=memo):yield zself.stackVals.pop()elif tObj in [types.ListType,types.TupleType]:for i,x in enumerate(obj):listTuple = ('listLike',i)self.stackVals.append(listTuple)for z in self.run(x,memo=memo):yield zself.stackVals.pop()else: # objects or uncaught types...### from http://bugs.python.org/file18699/static.pytry:instance_dict = object.__getattribute__(obj,"__dict__")except AttributeError:## probably uncaught static objectreturnfor x in instance_dict:try:gotValue = object.__getattribute__(obj,x)except: # ?? property that relies on something else being set.continueobjTuple = ('getattr',x)self.stackVals.append(objTuple)try:for z in self.run(gotValue,memo=memo):yield zexcept RuntimeError:raise Exception("Maximum recursion on:\n%s" % self.currentLevel())self.stackVals.pop()self.currentStack.pop()def currentLevel(self):currentStr = ""for stackType,stackValue in self.stackVals:if stackType == 'dict':if isinstance(stackValue,str):currentStr += "['" + stackValue + "']"elif isinstance(stackValue,unicode):currentStr += "[u'" + stackValue + "']"else: # numeric key...currentStr += "[" + str(stackValue) + "]"elif stackType == 'listLike':currentStr += "[" + str(stackValue) + "]"elif stackType == 'getattr':currentStr += ".__getattribute__('" + stackValue + "')"else:raise Exception("Cannot get attribute of type %s" % stackType)return currentStr
class Mock(object):def __init__(self,mockThing,embedMock = True):self.abby = 30self.mocker = mockThingself.mockList = [mockThing,40]self.embeddedMock = Noneif embedMock is True:self.embeddedMock = Mock(mockThing,embedMock = False)mockType = lambda x: x.__class__.__name__ == 'Mock'subList = [100,60,-2]myList = [5,20,[5,12,17],30,{'hello': 10,'goodbye': 22,'mock': Mock(subList)},-20,Mock(subList)]myList.append(myList)ty = TreeYielder(mockType)for val in ty.run(myList):print(val,ty.currentLevel())
得到：
(<__main__.Mock object at 0x01DEBD10>,"[4]['mock']")(<__main__.Mock object at 0x01DEF370>,"[4]['mock'].__getattribute__('embeddedMock')")(<__main__.Mock object at 0x01DEF390>,'[6]')(<__main__.Mock object at 0x01DEF3B0>,"[6].__getattribute__('embeddedMock')")
或运行：
high = lambda x: isinstance(x,(int,float)) and x > 10ty = TreeYielder(high)for val in ty.run(myList):print(val,ty.currentLevel())
得到：
(20,'[1]')(12,'[2][1]')(17,'[2][2]')(30,'[3]')(22,"[4]['goodbye']")(100,"[4]['mock'].__getattribute__('embeddedMock').__getattribute__('mocker')[0]")(60,"[4]['mock'].__getattribute__('embeddedMock').__getattribute__('mocker')[1]")(40,"[4]['mock'].__getattribute__('embeddedMock').__getattribute__('mockList')[2]")
我还在试图找出为什么没有找到.abby,但我认为即使在这一点上它也值得发布,因为它比我开始时的正确轨道要多得多.