ruamel.yaml

0.19.1 · active · verified Sat Mar 28

ruamel.yaml is a YAML parser and emitter for Python that supports round-trip preservation of comments, sequence and mapping flow styles, and map key order. The current version is 0.19.1, released on March 28, 2026. It is actively maintained with regular updates.

Warnings

breaking The 'load' method in ruamel.yaml requires a file object, not a string. Ensure you open the file before passing it to 'load'.
Fix: Open the file using 'with open()' before passing it to 'load'.
gotcha The 'YAML' class is case-sensitive. Using 'yaml' instead of 'YAML' will result in an AttributeError.
Fix: Always import 'ruamel.yaml' as 'YAML' to access the 'YAML' class.

Install

pip install ruamel.yaml Install ruamel.yaml

Imports

YAML
```
import ruamel.yaml as YAML
```
Ensure 'ruamel.yaml' is imported as 'YAML' to access the 'YAML' class.

Quickstart

A basic example demonstrating how to load, modify, and save YAML data using ruamel.yaml.

import os
import ruamel.yaml as YAML

# Load YAML data
with open(os.environ.get('YAML_FILE_PATH', 'data.yaml'), 'r') as file:
    data = YAML().load(file)

# Modify data
data['new_key'] = 'new_value'

# Save YAML data
with open(os.environ.get('YAML_FILE_PATH', 'data.yaml'), 'w') as file:
    YAML().dump(data, file)

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