I have a yaml file that looks like
--- 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
I am able to read this correctly in Perl using YAML but not in python using YAML. It fails with the error:
expected a single document in the stream
Program:
import yaml stram = open("test", "r") print yaml.load(stram)
Error:
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
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Answer
The yaml documents are separated by ---
, and if any stream (e.g. a file) contains more than one document then you should use the yaml.load_all
function rather than yaml.load
. The code:
import yaml stream = open("test", "r") docs = yaml.load_all(stream, yaml.FullLoader) for doc in docs: for k,v in doc.items(): print k, "->", v print "n",
results in for the input file as provided in the question:
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