遍历嵌套字典树

Question

下面是树作为字典：

tree = {'X1': {0: {'X2': {0: 0, 1: {'X3': {0: 1, 1: 0}}}}, 1: {'X3': {0: 1, 1: 0}}}} 

如何在python中遍历此树，仅print遍历节点？例如X1，X2 ......

Answer 1

如果值是嵌套的dict，则需要逐步执行dict的每个级别，打印出所有匹配的键，然后调用相同的函数（递归）：

tree = {'X1': {0: {'X2': {0: 0, 1: {'X3': {0: 1, 1: 0}}}}, 1: {'X3': {0: 1, 1: 0}}}}

def recurse(d):
  for x, v in d.items():
    if str(x).startswith('X'):
        print(x)
    if isinstance(v, dict):
      recurse(v)

recurse(tree)