From 8ac409b1ed35e9eb93f33ee7d80df6742ad7014c Mon Sep 17 00:00:00 2001
From: janezd <janez.demsar@fri.uni-lj.si>
Date: Fri, 19 Feb 2021 11:54:27 +0100
Subject: [PATCH] Table.concatenate: Refactor

---
 Orange/data/table.py            | 50 ++++++++++++++++-----------------
 Orange/data/tests/test_table.py | 12 ++++++++
 2 files changed, 36 insertions(+), 26 deletions(-)

diff --git a/Orange/data/table.py b/Orange/data/table.py
index 059148a5c96..cf421c8aba8 100644
--- a/Orange/data/table.py
+++ b/Orange/data/table.py
@@ -898,11 +898,11 @@ def __repr__(self):
     @classmethod
     def concatenate(cls, tables, axis=0):
         """
-        Concatenate tables into a new table, either horizontally or vertically.
+        Concatenate tables into a new table, either vertically or horizontally.
 
-        If axis=0 (horizontal concatenate), all tables must have the same domain.
+        If axis=0 (vertical concatenate), all tables must have the same domain.
 
-        If axis=1 (vertical),
+        If axis=1 (horizontal),
         - all variable names must be unique.
         - ids are copied from the first table.
         - weights are copied from the first table in which they are defined.
@@ -915,12 +915,28 @@ def concatenate(cls, tables, axis=0):
         Returns:
             table (Table)
         """
+        if axis not in (0, 1):
+            raise ValueError("invalid axis")
+        if not tables:
+            raise ValueError('need at least one table to concatenate')
+
+        if len(tables) == 1:
+            return tables[0].copy()
+
         if axis == 0:
-            return cls._concatenate_vertical(tables)
-        elif axis == 1:
-            return cls._concatenate_horizontal(tables)
+            conc = cls._concatenate_vertical(tables)
         else:
-            raise ValueError("invalid axis")
+            conc = cls._concatenate_horizontal(tables)
+
+        # TODO: Add attributes = {} to __init__
+        conc.attributes = getattr(conc, "attributes", {})
+        for table in reversed(tables):
+            conc.attributes.update(table.attributes)
+
+        names = [table.name for table in tables if table.name != "untitled"]
+        if names:
+            conc.name = names[0]
+        return conc
 
     @classmethod
     def _concatenate_vertical(cls, tables):
@@ -941,10 +957,6 @@ def merge1d(arrs):
         def collect(attr):
             return [getattr(arr, attr) for arr in tables]
 
-        if not tables:
-            raise ValueError('need at least one table to concatenate')
-        if len(tables) == 1:
-            return tables[0].copy()
         domain = tables[0].domain
         if any(table.domain != domain for table in tables):
             raise ValueError('concatenated tables must have the same domain')
@@ -957,22 +969,12 @@ def collect(attr):
             merge1d(collect("W"))
         )
         conc.ids = np.hstack([t.ids for t in tables])
-        names = [table.name for table in tables if table.name != "untitled"]
-        if names:
-            conc.name = names[0]
-        # TODO: Add attributes = {} to __init__
-        conc.attributes = getattr(conc, "attributes", {})
-        for table in reversed(tables):
-            conc.attributes.update(table.attributes)
         return conc
 
     @classmethod
     def _concatenate_horizontal(cls, tables):
         """
         """
-        if not tables:
-            raise ValueError('need at least one table to join')
-
         def all_of(objs, names):
             return (tuple(getattr(obj, name) for obj in objs)
                     for name in names)
@@ -992,11 +994,7 @@ def stack(arrs):
 
         parts = all_of(doms, ("attributes", "class_vars", "metas"))
         domain = Domain(*(tuple(chain(*lst)) for lst in parts))
-        table = cls.from_numpy(domain, Xs, Ys, Ms, W, ids=tables[0].ids)
-        for ta in reversed(table_attrss):
-            table.attributes.update(ta)
-
-        return table
+        return cls.from_numpy(domain, Xs, Ys, Ms, W, ids=tables[0].ids)
 
     def add_column(self, variable, data, to_metas=None):
         """
diff --git a/Orange/data/tests/test_table.py b/Orange/data/tests/test_table.py
index 0c4bfbb0ac1..836110276b3 100644
--- a/Orange/data/tests/test_table.py
+++ b/Orange/data/tests/test_table.py
@@ -183,6 +183,18 @@ def test_concatenate_horizontal(self):
     def test_concatenate_invalid_axis(self):
         self.assertRaises(ValueError, Table.concatenate, (), axis=2)
 
+    def test_concatenate_names(self):
+        a, b, c, d, e, f, g = map(ContinuousVariable, "abcdefg")
+
+        tab1 = self._new_table((a, ), (c, ), (d, ), 0)
+        tab2 = self._new_table((e, ), (), (f, g), 1000)
+        tab3 = self._new_table((b, ), (), (), 1000)
+        tab2.name = "tab2"
+        tab3.name = "tab3"
+
+        joined = Table.concatenate((tab1, tab2, tab3), axis=1)
+        self.assertEqual(joined.name, "tab2")
+
     def test_with_column(self):
         a, b, c, d, e, f, g = map(ContinuousVariable, "abcdefg")
         col = np.arange(9, 14)