yayaml

yayaml#

The yayaml package provides extensions to ruamel.yaml that allow creating some often-needed Python objects directly via YAML tags and making it easier to represent custom objects when writing YAML files.

Features:

  • 40+ built-in YAML tags for common operations (math, strings, paths, etc.)

  • Easy creation of custom constructors and representers

  • Seamless integration with ruamel.yaml

  • Support for environment variables, conditionals, and NumPy arrays

Quick Example#

Use YAML tags to create Python objects directly:

# config.yml
sum:        !sum        [1, 2, 3]               # 6
formatted:  !format     ["{}+{}={}", 1, 2, 3]   # "1+2=3"
linspace:   !linspace   [-1, 1, 5]              # np.linspace(-1, 1, 5)
home_path:  !expanduser ~/config                # "/home/user/config"
username:   !getenv [USER, "unknown_user"]      # $USER or fallback

Load and use in Python:

import yayaml as yay

# Load YAML with built-in tags
config = yay.load_yml("config.yml")
print(config["sum"])  # 6

# Or load from string
data = yay.yaml.load("value: !sum [1, 2, 3]")

# Write YAML files
yay.write_yml({"key": "value"}, path="output.yml")
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