This is part of a series on data storage with Python.
In this post, we'll be covering .yaml files. YAML stands for "YAML Aint Markup Language", and it's a nice way for humans to read and edit several properties of some thing (e.g., an experiment, a piece of hardware, a server, etc...) A typical YAML document looks like this:
---
author: Jonathan Wheeler
email: jonathan.m.wheeler@gmail.com
favorite_foods:
- sandwiches
- pizza
- anything my wife makes
fake_birthday: 1992-01-23
pets:
lizard:
name: Henrietta
address: My wife's classroom at Mountain View Academy
squirrel:
name: Sammy the Squirrel
address: tree behind my house
biography: >
It was a dark and stormy day. Everything
seemed lost, until out of nowhere,
a man appeared with a unicycle...
The syntax is very easy to learn, and is very human-readable. Yaml documents are a great way to quickly write out settings or configurations by hand in a way that can later be read by a computer.
One of the things that I love about YAML files that they support working off a template. This is a great way to describe a large variety of configurations without having to repeat definitions. You can change all of the settings of a given type by just changing one line of code.
some_template: &foo
current: 10 mA
voltage: 100 mV
author: Jonathan
second_template: &bar
current: 20 mA
voltage: 100 mV
first_experiment:
<< : *foo # Loads in all of the variables in some_template
second_experiment:
<< : *foo # Loads in all of the variables in some_template
author: Jonathan's friend # Overwrites the author
In python, you can write data into a .yaml file with the following code:
import yaml
data = {
'author': 'Jonathan Wheeler',
'date': '2021-03-22',
'array': [1,2,3]
}
with open('somefile.yaml', 'w') as f:
f.write(yaml.dump(data))
And read it back with
with open('somefile.yaml') as f:
raw_contents = f.read()
data = yaml.load(raw_contents, Loader=yaml.FullLoader)
YAML excels with storing configurations and settings. It is not a very good format for storing large amounts of data, or when computers need to make more edits than humans do.
