atoti.MultiColumnArrayConversion#
- final class atoti.MultiColumnArrayConversion#
Convert an external table where array values are stored with one element per column to a table with array columns.
Groups of a least 2 columns named as
"f{prefix}_{index}"
(indices being consecutive and starting with 0 or 1) can be converted into array columns.Example
>>> external_database = session.connect_to_external_database(connection_config) >>> external_table = external_database.tables["TUTORIAL", "MULTI_COLUMN_QUANTITY"]
external_table
has 5 QUANTITY_{index} columns:>>> list(external_table) ['PRODUCT', 'QUANTITY_0', 'QUANTITY_1', 'QUANTITY_2', 'QUANTITY_3', 'QUANTITY_4']
and its content is:
PRODUCT
QUANTITY_0
QUANTITY_1
QUANTITY_2
QUANTITY_3
QUANTITY_4
product_1
10.0
20.0
15.0
25.0
10.0
product_2
50.0
65.0
55.0
30.0
80.0
It can be converted into a table with an array column:
>>> table = session.add_external_table( ... external_table, ... table_name="Sales (Multi column array)", ... config=TableConfig( ... keys=["PRODUCT"], ... array_conversion=tt.MultiColumnArrayConversion( ... column_prefixes={"QUANTITY"}, ... ), ... ), ... ) >>> table.head().sort_index() QUANTITY PRODUCT product_1 [10.0, 20.0, 15.0, 25.0, 10.0] product_2 [50.0, 65.0, 55.0, 30.0, 80.0]
See also