Add dots to alternating tabular lines

setup.py

@@ -10,6 +10,7 @@
     'scipy',
     'tabulate',
     'tensorboardX',
+    'wcwidth',
 ]
 
 extras = dict()

src/dowel/tabular_input.py

@@ -1,6 +1,7 @@
 """A `dowel.logger` input for tabular (key-value) data."""
 import contextlib
 import warnings
+import wcwidth
 
 import numpy as np
 import tabulate
@@ -24,8 +25,23 @@ def __init__(self):
 
     def __str__(self):
         """Return a string representation of the table for the logger."""
-        return tabulate.tabulate(
-            sorted(self.as_primitive_dict.items(), key=lambda x: x[0]))
+        # Sort first, then pad.
+        lines = sorted(self.as_primitive_dict.items(), key=lambda x: x[0])
+        key_widths = [wcwidth.wcswidth(key) for key, value in lines]
+        max_key_width = max(key_widths, default=0)
+        padded_keys = []
+        for line, (key, value) in enumerate(lines):
+            padded_key = key
+            if line % 2 == 1:
+                key_width = wcwidth.wcswidth(key)
+                if key_width % 2 == 1 and key_width < max_key_width:
+                    padded_key += ' '
+                    key_width += 1
+                pad_width = (max_key_width - key_width) // 2
+                padded_key += ' .' * pad_width
+            padded_keys.append(padded_key)
+        values = [value for key, value in lines]
+        return tabulate.tabulate(zip(padded_keys, values))
 
     def record(self, key, val):
         """Save key/value entries for the table.
@@ -55,11 +71,11 @@ def record_misc_stat(self, key, values, placement='back'):
         :param placement: Whether to put the prefix in front or in the back.
         """
         if placement == 'front':
-            front = ""
+            front = ''
             back = key
         else:
             front = key
-            back = ""
+            back = ''
         if values:
             self.record(front + 'Average' + back, np.average(values))
             self.record(front + 'Std' + back, np.std(values))

tests/dowel/test_simple_outputs.py

@@ -125,6 +125,36 @@ def test_record_tabular(self, mock_datetime):
         self.str_out.seek(0)
         assert self.str_out.read() == tab
 
+    def test_record_tabular_line_markers(self, mock_datetime):
+        fake_timestamp(mock_datetime)
+
+        self.tabular.record('a', 100)
+        self.tabular.record('bbbbbbb', 55)
+        self.tabular.record('ccccc', 55)
+        self.tabular.record('d', 55)
+        self.tabular.record('ee', 55)
+        self.tabular.record('ff', 55)
+
+        with redirect_stdout(self.str_out):
+            self.std_output.record(self.tabular)
+
+        self.std_output.dump()
+
+        tab = (
+            '-------  ---\n'
+            'a        100\n'
+            'bbbbbbb   55\n'
+            'ccccc     55\n'
+            'd  . .    55\n'
+            'ee        55\n'
+            'ff . .    55\n'
+            '-------  ---\n'
+        )  # yapf: disable
+        self.str_out.seek(0)
+        output = self.str_out.read()
+        print(output)
+        assert output == tab
+
     def test_record_with_timestamp(self, mock_datetime):
         fake_timestamp(mock_datetime)