不带标签的PyYAML转储Python对象

Question

如何使用PyYAML转储没有标记的Python对象？我有这样的课程：

class Monster(yaml.YAMLObject):
    yaml_tag = u'!Monster'
    def __init__(self, name, hp, ac, attacks):
        self.name = name
        self.hp = hp
        self.ac = ac
        self.attacks = attacks

然后我试着转储：

print(yaml.dump(Monster(name='Cave lizard', hp=[3,6], ac=16, attacks=['BITE','HURT'])))

并得到了结果：

!Monster
ac: 16
attacks: [BITE, HURT]
hp: [3, 6]
name: Cave lizard

但期望的结果是：

ac: 16
attacks: [BITE, HURT]
hp: [3, 6]
name: Cave lizard

我怎么才能得到这个呢？

Answer 1

由于您不想发出标记，因此应该将执行此操作的方法更改为no-op：

import yaml
import sys

class Monster(yaml.YAMLObject):
    yaml_tag = u'!Monster'
    def __init__(self, name, hp, ac, attacks):
        self.name = name
        self.hp = hp
        self.ac = ac
        self.attacks = attacks

def noop(self, *args, **kw):
    pass

yaml.emitter.Emitter.process_tag = noop

yaml.dump([
    Monster(name='Cave lizard', hp=[3,6], ac=16, attacks=['BITE','HURT']),
    Monster(name='Sméagol', hp=400, ac=14, attacks=['TOUCH','EAT-GOLD']),
], sys.stdout, allow_unicode=True)

这就给出了：

- ac: 16
  attacks: [BITE, HURT]
  hp: [3, 6]
  name: Cave lizard
- ac: 14
  attacks: [TOUCH, EAT-GOLD]
  hp: 400
  name: Sméagol

请注意，使用print(yaml.dump())在时间和内存上的效率很低。PyYAML有一个流式接口，所以您应该直接使用它，而不是先流式传输到缓冲区，然后再使用print()流式传输缓冲区