Slug now accepts multiple column names to merge. Closes wireservice#617

agate/computations/slug.py

@@ -4,15 +4,18 @@
 from agate.computations.base import Computation
 from agate.data_types import Text
 from agate.exceptions import DataTypeError
-from agate.utils import slugify
+from agate.utils import slugify, issequence
 
 
 class Slug(Computation):
     """
-    Convert text values into a column into slugs.
+    Convert text values from one or more columns into slugs. If multiple column
+    names are given, values from those columns will be appended in the given
+    order before standardizing.
 
     :param column_name:
-        The name of a column containing the :class:`.Text` values.
+        The name of a column or a sequence of column names containing
+        :class:`.Text` values.
     :param ensure_unique:
         If True, any duplicate values will be appended with unique identifers.
         Defaults to False.
@@ -26,13 +29,19 @@ def get_computed_data_type(self, table):
         return Text()
 
     def validate(self, table):
-        column = table.columns[self._column_name]
+        if issequence(self._column_name):
+            column_names = self._column_name
+        else:
+            column_names = [self._column_name]
 
-        if not isinstance(column.data_type, Text):
-            raise DataTypeError('Slug column must contain Text data.')
+        for column_name in column_names:
+            column = table.columns[column_name]
 
-        if HasNulls(self._column_name).run(table):
-            raise ValueError('Slug column cannot contain `None`.')
+            if not isinstance(column.data_type, Text):
+                raise DataTypeError('Slug column must contain Text data.')
+
+            if HasNulls(column_name).run(table):
+                raise ValueError('Slug column cannot contain `None`.')
 
     def run(self, table):
         """
@@ -42,6 +51,13 @@ def run(self, table):
         new_column = []
 
         for row in table.rows:
-            new_column.append(row[self._column_name])
+            if issequence(self._column_name):
+                column_value = ''
+                for column_name in self._column_name:
+                    column_value = column_value + ' ' + row[column_name]
+
+                new_column.append(column_value)
+            else:
+                new_column.append(row[self._column_name])
 
         return slugify(new_column, ensure_unique=self._ensure_unique, **self._slug_args)

tests/test_computations.py

@@ -365,6 +365,36 @@ def test_slug(self):
         )
         expected = ['hello-world', 'ab-c-e', 'he11o-w0rld']
 
+        table = Table(rows, ['one', 'two'], [self.text_type, self.number_type]).compute([
+            ('slugs', Slug('one'))
+        ])
+
+        self.assertSequenceEqual(table.columns['slugs'], expected)
+
+    def test_slug_column_name_sequence(self):
+        rows = (
+            ('hello world', 2, 'Ab*c #e'),
+            ('Ab*c #e', 2, 'He11O W0rld'),
+            ('He11O W0rld', 3, 'hello world')
+        )
+        expected = ['hello-world-ab-c-e', 'ab-c-e-he11o-w0rld', 'he11o-w0rld-hello-world']
+
+        table1 = Table(rows, ['one', 'two', 'three'], [self.text_type, self.number_type, self.text_type])
+        table2 = table1.compute([
+            ('slugs', Slug(['one', 'three']))
+        ])
+
+        self.assertSequenceEqual(table2.columns['slugs'], expected)
+
+    def test_slug_ensure_unique(self):
+        rows = (
+            ('hello world', 2),
+            ('Ab*c #e', 2),
+            ('He11O W0rld', 3),
+            ('HellO WOrld ', 3)
+        )
+        expected = ['hello-world', 'ab-c-e', 'he11o-w0rld', 'hello-world-1']
+
         table = Table(rows, ['one', 'two'], [self.text_type, self.number_type]).compute([
             ('slugs', Slug('one', ensure_unique=True))
         ])