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Expectation Suite Operations

A Great Expectations Expectation Suite enables you to perform Create, Read, Update, and Delete (CRUD) operations on a Suite's Expectations without needing to re-run them. Each of the methods that support a CRUD operation relies on two main parameters - expectation_configuration and match_type.

  • expectation_configuration - an ExpectationConfiguration object that is used to determine whether and where this Expectation already exists within the Suite. It can be a complete or a partial ExpectationConfiguration.
  • match_type - a string with the value of domain, success, or runtime which determines the criteria used for matching:
    • domain checks whether two Expectation Configurations apply to the same data. It results in the loosest match, and can use the least complete ExpectationConfiguration object. For example, for a column map Expectation, domain_kwargs will include the Expectation_type, the column, and any row_conditions that may affect which rows are evaluated by the Expectation.
    • success criteria are more exacting - in addition to the domain kwargs, these include those kwargs used when evaluating the success of an Expectation, like mostly, max, or value_set.
    • runtime are the most specific - in addition to domain_kwargs and success_kwargs, these include kwargs used for runtime configuration. Currently these include result_format, include_config, and catch_exceptions

Adding or updating Expectations​

To add an Expectation to a Suite, you can use

suite.add_expectation(
    expectation_configuration, 
    match_type, 
    overwrite_existing
)
  • If a matching Expectation is not found on the Suite, this function will add the Expectation to the Suite.
  • If a matching Expectation is found on the Suite, add_expectation will throw an error, unless overwrite_existing is set to True, in which case the found Expectation will be updated with expectation_configuration.
  • If more than one Expectation is found, this will throw an error, and you will be prompted to be more specific with your matching criteria.

Removing Expectations​

To remove an Expectation from an Expectation Suite, you can use

suite.remove_expectation(
    expectation_configuration, 
    match_type, 
    remove_multiple_matches
)
  • If this finds one matching Expectation, it will remove it.
  • If it finds more than one matching Expectation, it will throw an error, unless remove_multiple_matches is set to True, in which case it will remove all matching Expectations.
  • If this finds no matching Expectations, it will throw an error.

If you are interactively working with an Expectation Suite using a Validator, you can access this functionality by directly calling 

validator.remove_expectation(
    expectation_configuration, 
    match_type, 
    remove_multiple_matches
)