解决：python 递归结束时，储存的中间变量消失了

写了一个递归函数，将一棵字典树的每一条分支解析出来，结果发现每次递归结束后，存储每一个分支的列表都突然变空

def tree_to_code(myTree,nodeTxt,rulelist,rulelib):
    firstStr = list(myTree.keys())[0]
    #print("*",firstStr)
    rulelist.append(firstStr)
    secondDict = myTree[firstStr]
    for key in secondDict.keys():
        if type(secondDict[key]).__name__ == 'dict':
            rulelist.append(key)
            #print("**", key)
            tree_to_code(secondDict[key], str(key),rulelist,rulelib)

        else:
            rulelist.append(key)
            rulelist.append(secondDict[key])
            rulelib.ruleset.append(rulelist)
            print(rulelist)
            rulelist.pop()
            rulelist.pop()
    if rulelist:
        rulelist.pop()
    if rulelist:
        rulelist.pop()

参考了这个博主的文章
python 递归时存储中间变量要用copy 方法，否则出栈就废了_yyt200808的博客-CSDN博客

这一行直接复制就可以了

def tree_to_code(myTree,nodeTxt,rulelist,rulelib):
    firstStr = list(myTree.keys())[0]
    #print("*",firstStr)
    rulelist.append(firstStr)
    secondDict = myTree[firstStr]
    for key in secondDict.keys():
        if type(secondDict[key]).__name__ == 'dict':
            rulelist.append(key)
            #print("**", key)
            tree_to_code(secondDict[key], str(key),rulelist,rulelib)

        else:
            rulelist.append(key)
            rulelist.append(secondDict[key])
            rulecopy=rulelist.copy()
            rulelib.ruleset.append(rulecopy)
            print(rulelist)
            rulelist.pop()
            rulelist.pop()
    if rulelist:
        rulelist.pop()
    if rulelist:
        rulelist.pop()