Merge pull request #633 from orsharir/master

Add a global ‘max_precision’ argument to print_table

AUTHORS.rst

@@ -17,3 +17,4 @@ agate is made by a community. The following individuals have contributed code, d
 * `Ben Welsh <https://github.com/palewire>`_
 * `Kevin Schaul <https://github.com/kevinschaul>`_
 * `Eli Murray <https://github.com/ejmurra>`_
+* `Or Sharir <https://github.com/orsharir>`_

agate/table/print_table.py

@@ -11,7 +11,7 @@
 from agate import utils
 
 
-def print_table(self, max_rows=20, max_columns=6, output=sys.stdout, max_column_width=20, locale=None):
+def print_table(self, max_rows=20, max_columns=6, output=sys.stdout, max_column_width=20, locale=None, max_precision=3):
     """
     Print a text-based view of the data in this table.
 
@@ -31,13 +31,20 @@ def print_table(self, max_rows=20, max_columns=6, output=sys.stdout, max_column_
     :param locale:
         Provide a locale you would like to be used to format the output.
         By default it will use the system's setting.
+    :max_precision:
+        Puts a limit on the maximum precision displayed for number types.
+        Numbers with lesser precision won't be affected.
+        This defaults to :code:`3`. Pass :code:`None` to disable limit.
     """
     if max_rows is None:
         max_rows = len(self._rows)
 
     if max_columns is None:
         max_columns = len(self._columns)
 
+    if max_precision is None:
+        max_precision = float('inf')
+
     ellipsis = config.get_option('ellipsis_chars')
     vertical_line = config.get_option('vertical_line_char')
     locale = locale or config.get_option('default_locale')
@@ -66,7 +73,11 @@ def print_table(self, max_rows=20, max_columns=6, output=sys.stdout, max_column_
 
         if isinstance(c.data_type, Number):
             max_places = utils.max_precision(c[:max_rows])
-            number_formatters.append(utils.make_number_formatter(max_places))
+            add_ellipsis = False
+            if max_places > max_precision:
+                add_ellipsis = True
+                max_places = max_precision
+            number_formatters.append(utils.make_number_formatter(max_places, add_ellipsis))
         else:
             number_formatters.append(None)
 

agate/utils.py

@@ -190,14 +190,19 @@ def max_precision(values):
     return max_decimal_places
 
 
-def make_number_formatter(decimal_places):
+def make_number_formatter(decimal_places, add_ellipsis=False):
     """
     Given a number of decimal places creates a formatting string that will
     display numbers with that precision.
-    """
-    fraction = '0' * decimal_places
 
-    return ''.join(['#,##0.', fraction, ';-#,##0.', fraction])
+    :param decimal_places:
+        The number of decimal places
+    :param add_ellipsis:
+        Optionally add an ellipsis symbol at the end of a number
+    """
+    fraction = u'0' * decimal_places
+    ellipsis = u'…' if add_ellipsis else u''
+    return u''.join([u'#,##0.', fraction, ellipsis, u';-#,##0.', fraction, ellipsis])
 
 
 def round_limits(minimum, maximum):

tests/test_table/test_print_table.py

@@ -57,6 +57,38 @@ def test_print_table_max_columns(self):
         self.assertEqual(len(lines), 8)
         self.assertEqual(len(lines[0]), 25)
 
+    def test_print_table_max_precision(self):
+        rows = (
+            ('1.745', 1.745, 1.72),
+            ('11.123456', 11.123456, 5.10),
+            ('0', 0, 0.10)
+        )
+
+        column_names = ['text_number', 'real_long_number', 'real_short_number']
+        column_types = [
+            self.text_type,
+            self.number_type,
+            self.number_type
+        ]
+        table = Table(rows, column_names, column_types)
+
+        output = six.StringIO()
+        table.print_table(output=output, max_precision=2)
+        lines = output.getvalue().split('\n')
+
+        # Text shouldn't be affected
+        self.assertIn(u' 1.745 ', lines[3])
+        self.assertIn(u' 11.123456 ', lines[4])
+        self.assertIn(u' 0 ', lines[5])
+        # Test real precision above max
+        self.assertIn(u' 1.74… ', lines[3])
+        self.assertIn(u' 11.12… ', lines[4])
+        self.assertIn(u' 0.00… ', lines[5])
+        # Test real precision below max
+        self.assertIn(u' 1.72 ', lines[3])
+        self.assertIn(u' 5.10 ', lines[4])
+        self.assertIn(u' 0.10 ', lines[5])
+
     def test_print_table_max_column_width(self):
         rows = (
             ('1.7', 2, 'this is long'),