Parsing a YAML file in Python, and accessing the data?

Question

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?

Asked By: 9monkeys

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Source

Answer 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.

Answered By: Aphex

Answer 2

Just an FYI on @Aphex’s solution –

In case you run into –

"YAMLLoadWarning: calling yaml.load() without Loader=… is deprecated"

you may want to use the Loader=yaml.FullLoader or Loader=yaml.SafeLoader option.

import yaml 

with open('cc_config.yml', 'r') as f:
    doc = yaml.load(f, Loader=yaml.FullLoader) # also, yaml.SafeLoader

txt = doc["treeroot"]["branch1"]
print (txt)

Answered By: Raja Sarkar

Parsing a YAML file in Python, and accessing the data?

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