使用PyYAML获取YAML中的所有子项键值

如果只想检查标量值,可以使用低级事件API:

import yaml
import sys

input = """
Resources:
  AlarmTopic:
    Type: AWS::SNS::Topic
    Properties:
      Subscription:
        - !If
          - ShouldAlarm
          - Protocol: email
"""

for e in yaml.parse(input):
    if isinstance(e, yaml.ScalarEvent):
        print(e.value)

(我修复了你的YAML,因为它有语法错误。)这将产生:

Resources
AlarmTopic
Type
AWS::SNS::Topic
Properties
Subscription
ShouldAlarm
Protocol
email