Parsing a YAML file in Python, and accessing the d

问题:

I am new to YAML and have been searching for ways to parse a YAML file and use/access the data from the parsed YAML.

I have come across explanations on how to parse the YAML file, for example, the PyYAML tutorial, "How can I parse a YAML file in Python", "Convert Python dict to object?", but what I haven't found is a simple example on how to access the data from the parsed YAML file.

Assume I have a YAML file such as:

 treeroot:
     branch1: branch1 text
     branch2: branch2 text

How do I access the text "branch1 text"?

"YAML parsing and Python?" provides a solution, but I had problems accessing the data from a more complex YAML file. And, I'm wondering if there is some standard way of accessing the data from a parsed YAML file, possibly something similar to "tree iteration" or "elementpath" notation or something which would be used when parsing an XML file?

回答1:

Since PyYAML's yaml.load() function parses YAML documents to native Python data structures, you can just access items by key or index. Using the example from the question you linked:

import yaml
with open('tree.yaml', 'r') as f:
    doc = yaml.load(f)

To access branch1 text you would use:

txt = doc["treeroot"]["branch1"]
print txt
"branch1 text"

because, in your YAML document, the value of the branch1 key is under the treeroot key.