All of the above solutions are good, but they are not necessarily very robust to reformatting of the document, which appears to be YAML.
Normally this is where I’d recommend a plugin or a PythonScript solution for working with YAML, but I don’t know of any plugins, and Python’s YAML package is not in the Python standard library, so using PythonScript for YAML isn’t a great option.
Having said that, my general suggestion for performing these kinds of manipulations on YAML documents is to learn a scripting language (I recommend Python) and using that to write normal Python scripts. If you end up going that route, this forum will cease to be a useful resource and StackOverflow becomes one of your best friends.