python - 使用 Python 读取 YAML 文件会导致 yaml.composer.ComposerError: expected a single document in the stream

Question

我有一个看起来像的 yaml 文件

---
level_1: "test"
level_2: 'NetApp, SOFS, ZFS Creation'
request: 341570
---
level_1: "test"
level_2: 'NetApp, SOFS, ZFS Creation'
request: 341569
---
level_1: "test"
level_2: 'NetApp, SOFS, ZFS Creation'
request: 341568

我可以使用 YAML 在 Perl 中正确读取此内容，但不能在使用 YAML 的 python 中正确读取。它失败并出现错误：

期望流中有一个文档

程序：

import yaml

stram = open("test", "r")
print yaml.load(stram)

错误：

Traceback (most recent call last):
  File "abcd", line 4, in <module>
    print yaml.load(stram)
  File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/__init__.py", line 58, in load
    return loader.get_single_data()
  File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/constructor.py", line 42, in get_single_data
    node = self.get_single_node()
  File "/usr/local/pkgs/python-2.6.5/lib/python2.6/site-packages/yaml/composer.py", line 43, in get_single_node
    event.start_mark)
yaml.composer.ComposerError: expected a single document in the stream
  in "test", line 2, column 1
but found another document
  in "test", line 5, column 1

Answer 1

yaml 文档由 分隔---，如果任何流（例如文件）包含多个文档，那么您应该使用该yaml.load_all函数而不是yaml.load. 编码：

import yaml

stream = open("test", "r")
docs = yaml.load_all(stream)
for doc in docs:
    for k,v in doc.items():
        print k, "->", v
    print "\n",

结果为问题中提供的输入文件：

request -> 341570
level_1 -> test
level_2 -> NetApp, SOFS, ZFS Creation

request -> 341569
level_1 -> test
level_2 -> NetApp, SOFS, ZFS Creation

request -> 341568
level_1 -> test
level_2 -> NetApp, SOFS, ZFS Creation