Traitlets

Release

4.3.3

Date

Feb 27, 2021

Traitlets is a framework that lets Python classes have attributes with type checking, dynamically calculated default values, and ‘on change’ callbacks.

The package also includes a mechanism to use traitlets for configuration, loading values from files or from command line arguments. This is a distinct layer on top of traitlets, so you can use traitlets in your code without using the configuration machinery.

• Using Traitlets
  • Default values, and checking type and value
  • observe
  • Validation
• Trait Types
  • Numbers
  • Strings
  • Containers
  • Classes and instances
  • Miscellaneous
• Defining new trait types
• Traitlets API reference
  • Dynamic default values
  • Callbacks when trait attributes change
  • Validating proposed changes
• Configurable objects with traitlets.config
  • The main concepts
  • Configuration objects and files
  • Configuration files inheritance
  • Class based configuration inheritance
  • Command-line arguments
  • Design requirements
• Utils
  • Links
• Migration from Traitlets 4.0 to Traitlets 4.1
  • Separation of metadata and keyword arguments in TraitType contructors
  • Deprecation of on_trait_change
  • The new @observe decorator
  • dynamic defaults generation with decorators
  • Deprecation of magic method for cross-validation
  • Backward-compatible upgrades
• Changes in Traitlets
  • 4.3
  • 4.2
  • 4.1 - 2016-01-15
  • 4.0 - 2015-06-19