Add Column.set_index (#1982)

RELEASES.md

@@ -1,5 +1,14 @@
 # Enso Next
 
+## Libraries
+
+- Added `Column.set_index` to allow you to explicitly change the index for a
+  column ([#1982](https://github.com/enso-org/enso/pull/1982)). Also expanded
+  `Table.set_index` to accept columns, rather than just names of columns in the
+  table.
+
+## Tooling
+
 - Implement `library/preinstall` endpoint, allowing the IDE to request a library
   to be installed asynchronously before importing it, so that adding the import
   does not seem to freeze the compiler

distribution/lib/Standard/Table/0.2.28-SNAPSHOT/src/Data/Column.enso

@@ -690,11 +690,30 @@ type Column
 
        > Example
          Get the index from a column.
+
+             import Standard.Examples
+
+             example_index = Examples.decimal_column.index
     index : Column ! Table.No_Index_Set_Error
     index = case this.java_column.getIndex.toColumn of
         Nothing -> Error.throw Table.No_Index_Set_Error
         i -> Column i
 
+    ## Sets the index of this column, using the provided column.
+
+       Arguments:
+       - index: The column to use as the index to this column.
+
+       > Example
+         Index the decimal column by the integer column.
+
+             import Standard.Examples
+
+             example_set_index =
+                Examples.decimal_column.set_index Examples.integer_column
+    set_index : Column -> Column
+    set_index index = Column (this.java_column.setIndex index.java_column)
+
     ## Returns the value contained in this column at the given index.
 
        Arguments:

distribution/lib/Standard/Table/0.2.28-SNAPSHOT/src/Data/Table.enso

@@ -298,16 +298,19 @@ type Table
     ## Sets the index of this table, using the column with the provided name.
 
        Arguments:
-       - index: The name of the column to use as the index in this table.
+       - index: The name of the column to use as the index in this table, or the
+         column itself to use.
 
        > Example
          Set the index of the inventory table to be the item name.
 
              import Standard.Examples
 
              example_set_index = Examples.inventory_table.set_index "item_name"
-    set_index : Text -> Table
-    set_index index = Table (this.java_table.indexFromColumn index)
+    set_index : Text | Column -> Table
+    set_index index = case index of
+        Text -> Table (this.java_table.indexFromColumn index)
+        Column.Column c -> Table (this.java_table.indexFromColumn c)
 
     ## Returns the index of this table, as a column that is indexed by itself.
 

std-bits/table/src/main/java/org/enso/table/data/index/Index.java

@@ -1,11 +1,9 @@
 package org.enso.table.data.index;
 
-import org.enso.table.data.column.storage.Storage;
-import org.enso.table.data.mask.OrderMask;
-import org.enso.table.data.table.Column;
-
 import java.util.BitSet;
 import java.util.List;
+import org.enso.table.data.mask.OrderMask;
+import org.enso.table.data.table.Column;
 
 /** A storage class for ordered multisets. */
 public abstract class Index {

std-bits/table/src/main/java/org/enso/table/data/table/Column.java

@@ -9,6 +9,7 @@
 import org.enso.table.data.column.storage.BoolStorage;
 import org.enso.table.data.column.storage.Storage;
 import org.enso.table.data.index.DefaultIndex;
+import org.enso.table.data.index.HashIndex;
 import org.enso.table.data.index.Index;
 import org.enso.table.data.mask.OrderMask;
 import org.enso.table.error.UnexpectedColumnTypeException;
@@ -133,6 +134,18 @@ public Column withIndex(Index ix) {
     return new Column(name, ix, storage);
   }
 
+  /**
+   * Sets the index of this column to the provided column.
+   *
+   * @param col the column to use as the index.
+   * @return a column indexed by {@code col}
+   */
+  public Column setIndex(Column col) {
+    Storage storage = col.getStorage();
+    Index ix = HashIndex.fromStorage(col.getName(), storage);
+    return this.withIndex(ix);
+  }
+
   /** @return the index of this column */
   public Index getIndex() {
     return index;

std-bits/table/src/main/java/org/enso/table/data/table/Table.java

@@ -1,8 +1,12 @@
 package org.enso.table.data.table;
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.BitSet;
+import java.util.List;
+import java.util.Objects;
+import java.util.Set;
 import java.util.stream.Collectors;
-
 import org.enso.table.data.column.builder.object.InferredBuilder;
 import org.enso.table.data.column.storage.BoolStorage;
 import org.enso.table.data.column.storage.Storage;
@@ -157,12 +161,10 @@ public Index getIndex() {
   /**
    * Reindexes this table by using values from the column with the given name.
    *
-   * @param name the column name to use as index
+   * @param col the column to use as index
    * @return a table indexed by the proper column
    */
-  public Table indexFromColumn(String name) {
-    Column col = getColumnByName(name);
-    if (col == null) throw new NoSuchColumnException(name);
+  public Table indexFromColumn(Column col) {
     Storage storage = col.getStorage();
     Index ix = HashIndex.fromStorage(col.getName(), storage);
     List<Column> newColumns = new ArrayList<>();
@@ -171,13 +173,25 @@ public Table indexFromColumn(String name) {
       newColumns.add(indexCol.withIndex(ix));
     }
     for (Column column : columns) {
-      if (!column.getName().equals(name)) {
+      if (!column.getName().equals(col.getName())) {
         newColumns.add(column.withIndex(ix));
       }
     }
     return new Table(newColumns.toArray(new Column[0]), ix);
   }
 
+  /**
+   * Reindexes this table by using values from the column with the given name.
+   *
+   * @param name the column name to use as index
+   * @return a table indexed by the proper column
+   */
+  public Table indexFromColumn(String name) {
+    Column col = getColumnByName(name);
+    if (col == null) throw new NoSuchColumnException(name);
+    return indexFromColumn(col);
+  }
+
   /**
    * Selects a subset of columns of this table, by names.
    *

test/Table_Tests/src/Column_Spec.enso

@@ -1,6 +1,7 @@
 from Standard.Base import all
 from Standard.Table import all
 
+import Standard.Examples
 import Standard.Table.Data.Column
 import Standard.Test
 
@@ -59,3 +60,7 @@ spec = Test.group "Columns" <|
         c_2 = Column.from_vector "c_2" ["foo", "bar", "foo", "baz", "bar"]
         c_2.duplicate_count.to_vector.should_equal [0, 0, 1, 0, 1]
 
+    Test.specify "should allow setting their index" <|
+        col = Examples.decimal_column.set_index Examples.integer_column
+        col.index.to_vector . should_equal Examples.integer_column.to_vector
+

test/Table_Tests/src/Table_Spec.enso

@@ -496,6 +496,7 @@ spec =
 
     Test.group "Index" <|
         t = Table.new [['ix', [1, 2, 3]], ['c1', [4, 5, 6]]] . set_index 'ix'
+        c = Column.from_vector "name" ["a", "b", "c"]
         Test.specify "should be accessible by `at` like other columns" <|
             c = t.at 'ix'
             i = t.index
@@ -504,6 +505,10 @@ spec =
         Test.specify "should be accessible by `select` like other columns" <|
             t.select ['ix'] . columns . first . to_vector . should_equal t.index.to_vector
 
+        Test.specify "should be able to be set by column" <|
+            with_index = t.set_index c
+            with_index.index.to_vector . should_equal c.to_vector
+
     Test.group "Slicing Tables" <|
         Test.specify 'should allow taking first n rows' <|
             i_1 = ['ix', [1, 2, 3]]