Update tabular_writer to include option to not sort rows

pyomo/common/formatting.py

@@ -102,7 +102,7 @@ def tostr(value, quote_str=False):
 }
 
 
-def tabular_writer(ostream, prefix, data, header, row_generator):
+def tabular_writer(ostream, prefix, data, header, row_generator, sort_rows=True):
     """Output data in tabular form
 
     Parameters
@@ -121,7 +121,8 @@ def tabular_writer(ostream, prefix, data, header, row_generator):
         returns either a tuple defining the entries for a single row, or
         a generator that returns a sequence of table rows to be output
         for the specified `key`
-
+    sort_rows: bool
+        sets if rows should be sorted using robust_sort, default (True)
     """
 
     prefix = tostr(prefix)
@@ -186,7 +187,11 @@ def tabular_writer(ostream, prefix, data, header, row_generator):
 
     if any(' ' in r[-1] for x in _rows.values() if x is not None for r in x):
         _width[-1] = '%s'
-    for _key in sorted_robust(_rows):
+    if sort_rows:
+        _sorted_rows = sorted_robust(_rows)
+    else:
+        _sorted_rows = _rows
+    for _key in _sorted_rows:
         _rowSet = _rows[_key]
         if not _rowSet:
             _rowSet = [[_key] + [None] * (len(_width) - 1)]

pyomo/common/tests/test_formatting.py

@@ -129,6 +129,25 @@ def _data_gen(i, j):
 """
         self.assertEqual(ref.strip(), os.getvalue().strip())
 
+    def test_multiline_generator_user_sorted(self):
+        os = StringIO()
+        data = {"b": 0, "a": 1, "c": 3}
+
+        def _data_gen(i, j):
+            for n in range(j):
+                yield (n, chr(ord("a") + n) * j)
+
+        tabular_writer(os, "", data.items(), ["i", "j"], _data_gen, sort_rows=False)
+        ref = """
+Key : i    : j
+  b : None : None
+  a :    0 :    a
+  c :    0 :  aaa
+    :    1 :  bbb
+    :    2 :  ccc
+"""
+        self.assertEqual(ref.strip(), os.getvalue().strip())
+
     def test_multiline_generator_exception(self):
         os = StringIO()
         data = {'a': 0, 'b': 1, 'c': 3}