Concatenate Tables

Stack tables into one

how decides what concat() does when the inputs do not line up.

❯make a new table that takes the sales_east and sales_west tables and stacks their rows into one table

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Needs a transformer. Getting its guide.

Called tabsdata 2 times (ctrl+o to expand)

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Generating — concat() appends rows, and the default how="vertical" is right here because both inputs carry the same three columns with the same types.

Called tabsdata 3 times (ctrl+o to expand)

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The transformer, registered in subscriptions:

@transformer(
  input_tables=["sales_east", "sales_west"],
  output_tables=["sales_all"],
)
def combine_sales(east: TableFrameSpec, west: TableFrameSpec) -> TableFrameSpec:
  return concat([east, west])

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Execution committed, 0 failures.

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subscriptions/sales_all is live — 2 rows from sales_east then 2 from sales_west, in that order, columns unchanged:

┌────────┬───────┬────────┐
│ region │ month │ amount │
├────────┼───────┼────────┤
│ east   │ jan   │ 10     │
├────────┼───────┼────────┤
│ east   │ feb   │ 20     │
├────────┼───────┼────────┤
│ west   │ jan   │ 30     │
├────────┼───────┼────────┤
│ west   │ feb   │ 40     │
└────────┴───────┴────────┘

Transformed tables

sales_east

region	month	amount
east	jan	10
east	feb	20

2 rows

sales_west

region	month	amount
west	jan	30
west	feb	40

2 rows

sales_all

region	month	amount
east	jan	10
east	feb	20
west	jan	30
west	feb	40

4 rows

note

None entries in the list are skipped. A list that is None, empty, or empty once the None entries are dropped makes concat() return None, which leaves the output table on its current version instead of committing a new one.