Distinctness
Distinctness(dataset, column_list=None, filter_condition_dict=None, dataset_filter_by_data_type=None, duckdb_connection=None, decimal_places=2)
¶
Calculate distinctness (ratio of unique values) for specified columns using DuckDB.
Distinctness measures the proportion of unique values in columns, providing insights into data cardinality and quality. It is calculated as: COUNT(DISTINCT column) / COUNT(column)
Example
Given column values ["A", "B", "A", "C", "B", "D"]: - Distinct values: 4 (A, B, C, D) - Total values: 6 - Distinctness ratio = 4/6 ≈ 0.67 - Distinctness percentage = 67%
Parameters:
Name | Type | Description | Default |
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dataset
|
Any
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Input dataset as DataFrame or table name string. For DataFrames with duckdb_connection, registers as temporary table. |
required |
column_list
|
Optional[List[str]]
|
Optional list of column names to analyze. Can combine with dataset_filter_by_data_type. |
None
|
filter_condition_dict
|
Optional[Dict[str, Union[str, int, float]]]
|
Optional filter conditions as {'column': value} dict. Example: {'category': 'electronics', 'price': 100} |
None
|
dataset_filter_by_data_type
|
Optional[List[str]]
|
Optional data types to filter columns. Example: ['VARCHAR', 'INTEGER']. Can combine with column_list. |
None
|
duckdb_connection
|
Optional[DuckDBPyConnection]
|
Optional existing DuckDB connection. Creates new connection if None. |
None
|
decimal_places
|
int
|
Number of decimal places for rounding distinctness values. |
2
|
Returns:
Type | Description |
---|---|
List[Dict[str, Union[str, float, dict, None]]]
|
List of dicts with analysis results: |
List[Dict[str, Union[str, float, dict, None]]]
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List[Dict[str, Union[str, float, dict, None]]]
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List[Dict[str, Union[str, float, dict, None]]]
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List[Dict[str, Union[str, float, dict, None]]]
|
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List[Dict[str, Union[str, float, dict, None]]]
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List[Dict[str, Union[str, float, dict, None]]]
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List[Dict[str, Union[str, float, dict, None]]]
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Raises:
Type | Description |
---|---|
ValueError
|
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Source code in src/whistlingduck/analyzers/Distinctness.py
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