Docs
std.fact_table
← Stdlib Reference · Language Guide · Detailed reference
Columnar fact tables with hash indexes, grouping, aggregation, and a CSV
bridge. Built on the %fact-table-* runtime primitives.
(import std.fact_table)
Construction
| Symbol | Description |
|---|
(make-fact-table columns) | Create a table with the given column names. |
(fact-table? x) | True when x is a fact table. |
Mutation and indexing
| Symbol | Description |
|---|
(fact-table-insert! t row) | Append a row (alist or list matching column order). |
(fact-table-build-index! t cols) | Build a hash index over cols for fast queries. |
Query
| Symbol | Description |
|---|
(fact-table-query t bindings) | Return matching rows for the given column/value bindings. |
(fact-table-ref t row-index col) | Cell value. |
(fact-table-row-count t) | Number of rows. |
(fact-table-row t row-index) | Row as alist. |
(fact-table-for-each t f) | Apply f to each row. |
(fact-table-filter t pred) | Return rows for which pred is true. |
(fact-table-fold t f init) | Left fold over rows. |
Aggregation
| Symbol | Description |
|---|
(fact-table-group-count t cols) | Count rows per distinct combination of cols. |
(fact-table-group-sum t cols sum-col) | Sum sum-col per group. |
(fact-table-group-by t cols) | Group rows by cols. |
(fact-table-partition t pred) | Two tables: rows passing and rows failing pred. |
CSV bridge
| Symbol | Description |
|---|
(fact-table-load-csv path) | Build a fact table from a CSV file (header required). |
(fact-table-save-csv t path) | Write a fact table to a CSV file. |
Source: stdlib/std/fact_table.eta
Eta