cscanlin / python-yamlordereddictloader

YAML loader and dumper for PyYAML allowing to keep keys order.

python-yamlordereddictloader

This module provide a loader and a dumper for PyYAML allowing to keep items order when loading a file (by putting them in OrderedDict objects) and to manage OrderedDict objects when dumping to a file.

The loader is based on stackoverflow topic (thanks to Eric Naeseth): http://stackoverflow.com/questions/5121931/in-python-how-can-you-load-yaml-mappings-as-ordereddicts#answer-5121963

Self promotion: I use it a lot with clg, which allows to generate command-line definition from a configuration file, for keeping order of subcommands, options and arguments in the help message!

To install it

$ pip install yamlordereddictloader

Loader usage

import yaml
import yamlordereddictloader

data = yaml.load(open('myfile.yml'), Loader=yamlordereddictloader.Loader)

Note: For using the safe loader (which want standard YAML tags and does not construct arbitrary Python objects), replace yamlorderdictloader.Loader by yamlorderedictloader.SafeLoader.

Dumper usage

import yaml
import yamlordereddictloader
from collections import OrderedDict

data = OrderedDict([
    ('key1', 'val1'),
    ('key2', OrderedDict([('key21', 'val21'), ('key22', 'val22')]))
])
yaml.dump(
    data,
    open('myfile.yml', 'w'),
    Dumper=yamlordereddictloader.Dumper,
    default_flow_style=False)

Note: For using the safe dumper (which produce standard YAML tags and does not represent arbitrary Python objects), replace yamlorderdictloader.Dumper by yamlorderedictloader.SafeDumper.