Allow Table.join to work with column ids. wireservice/csvkit#711

CHANGELOG.rst

@@ -1,6 +1,7 @@
 1.5.3
 -----
 
+* :meth:`.Table.join` can now accept column indicies instead of column names.
 * :meth:`.Table.from_csv` now buffers input files to prevent issues with using STDIN as an input.
 
 1.5.2 - December 24, 2016

agate/table/join.py

@@ -26,13 +26,13 @@ def join(self, right_table, left_key, right_key=None, inner=False, require_match
     :param right_table:
         The "right" table to join to.
     :param left_key:
-        Either the name of a column from the this table to join on, a
-        sequence of such column names, or a :class:`function` that takes a
-        row and returns a value to join on.
+        Either the name of a column from the this table to join on, the index
+        of a column, a sequence of such column identifiers, or a
+        :class:`function` that takes a row and returns a value to join on.
     :param right_key:
-        Either the name of a column from :code:table` to join on, a
-        sequence of such column names, or a :class:`function` that takes a
-        row and returns a value to join on. If :code:`None` then
+        Either the name of a column from :code:table` to join on, the index of
+        a column, a sequence of such column identifiers, or a :class:`function`
+        that takes a ow and returns a value to join on. If :code:`None` then
         :code:`left_key` will be used for both.
     :param inner:
         Perform a SQL-style "inner join" instead of a left outer join. Rows
@@ -83,7 +83,7 @@ def join(self, right_table, left_key, right_key=None, inner=False, require_match
     else:
         right_column = right_table._columns[right_key]
         right_data = right_column.values()
-        right_key_indices = [right_table._columns._keys.index(right_key)]
+        right_key_indices = [right_table._columns.index(right_column)]
 
     # Build names and type lists
     column_names = list(self._column_names)

tests/test_table/test_join.py

@@ -43,6 +43,19 @@ def test_join(self):
             (None, 2, 'c', 2, 'c')
         ])
 
+    def test_join_column_indicies(self):
+        new_table = self.left.join(self.right, 0, 0)
+
+        self.assertIsNot(new_table, self.left)
+        self.assertIsNot(new_table, self.right)
+        self.assertColumnNames(new_table, ['one', 'two', 'three', 'five', 'six'])
+        self.assertColumnTypes(new_table, [Number, Number, Text, Number, Text])
+        self.assertRows(new_table, [
+            (1, 4, 'a', 4, 'a'),
+            (2, 3, 'b', 3, 'b'),
+            (None, 2, 'c', 2, 'c')
+        ])
+
     def test_join_match_multiple(self):
         left_rows = (
             (1, 4, 'a'),