PyYAML只会默默覆盖第一个条目,ruamel.yaml¹将为DuplicateKeyFutureWarning
if(如果与旧版API一起使用),并DuplicateKeyError
为新API提出一个。
如果您不想Constructor
为所有类型创建一个全数,SafeConstructor
则应覆盖其中的映射构造函数来完成此工作:
import sys
from ruamel.yaml import YAML
from ruamel.yaml.constructor import SafeConstructor
yaml_str = """\
build:
step: 'step1'
build:
step: 'step2'
"""
def construct_yaml_map(self, node):
# test if there are duplicate node keys
data = []
yield data
for key_node, value_node in node.value:
key = self.construct_object(key_node, deep=True)
val = self.construct_object(value_node, deep=True)
data.append((key, val))
SafeConstructor.add_constructor(u'tag:yaml.org,2002:map', construct_yaml_map)
yaml = YAML(typ='safe')
data = yaml.load(yaml_str)
print(data)
这使:
[('build', [('step', 'step1')]), ('build', [('step', 'step2')])]
但是,似乎没有必要将step: 'step1'
其列入列表。以下仅在有重复项的情况下创建列表(可以通过缓存的结果进行优化,如有必要self.construct_object(key_node, deep=True)
):
def construct_yaml_map(self, node):
# test if there are duplicate node keys
keys = set()
for key_node, value_node in node.value:
key = self.construct_object(key_node, deep=True)
if key in keys:
break
keys.add(key)
else:
data = {} # type: Dict[Any, Any]
yield data
value = self.construct_mapping(node)
data.update(value)
return
data = []
yield data
for key_node, value_node in node.value:
key = self.construct_object(key_node, deep=True)
val = self.construct_object(value_node, deep=True)
data.append((key, val))
这使:
[('build', {'step': 'step1'}), ('build', {'step': 'step2'})]
一些要点:
yaml_out = YAML(typ='safe')
yaml_out.dump(data, sys.stdout)
给出(与第一个construct_yaml_map
):
- - build
- - [step, step1]
- - build
- - [step, step2]
from pathlib import Path # or: from ruamel.std.pathlib import Path
yaml = YAML(typ='safe')
yaml.load(Path('file.yml')
¹免责声明:我是该软件包的作者。