ContinuousVariable.str_val: Print two more decimals when outside rounding error

Author: janezd

Orange/data/tests/test_variable.py

@@ -498,23 +498,42 @@ def test_make(self):
 
     def test_decimals(self):
         a = ContinuousVariable("a", 4)
-        self.assertEqual(a.str_val(4.654321), "4.6543")
-        self.assertEqual(a.str_val(4.654321654321), "4.6543")
+        self.assertEqual(a.str_val(4.6543), "4.6543")
+        self.assertEqual(a.str_val(4.25), "4.2500")
         self.assertEqual(a.str_val(Unknown), "?")
         a = ContinuousVariable("a", 5)
         self.assertEqual(a.str_val(0.000000000001), "0.00000")
         a = ContinuousVariable("a", 10)
         self.assertEqual(a.str_val(0.000000000001), "1e-12")
 
+    def test_more_decimals(self):
+        a = ContinuousVariable("a", 0)
+        self.assertEqual(a.str_val(4), "4")
+        self.assertEqual(a.str_val(4.1234), "4.12")
+
+        a = ContinuousVariable("a", 2)
+        self.assertEqual(a.str_val(4), "4.00")
+        self.assertEqual(a.str_val(4.25), "4.25")
+        self.assertEqual(a.str_val(4.1234123), "4.1234")
+
+        for cca4 in (4 + 1e-9, 4 - 1e-9):
+            assert cca4 != 4
+            self.assertEqual(a.str_val(cca4), "4.00")
+
     def test_adjust_decimals(self):
+        # Default is 3 decimals, but format is %g
         a = ContinuousVariable("a")
+        self.assertEqual(a.str_val(5), "5")
         self.assertEqual(a.str_val(4.65432), "4.65432")
+
+        # Change to no decimals
         a.val_from_str_add("5")
-        self.assertEqual(a.str_val(4.65432), "5")
+        self.assertEqual(a.str_val(5), "5")
+
+        # Change to two decimals
         a.val_from_str_add("  5.12    ")
-        self.assertEqual(a.str_val(4.65432), "4.65")
-        a.val_from_str_add("5.1234")
-        self.assertEqual(a.str_val(4.65432), "4.6543")
+        self.assertEqual(a.str_val(4.65), "4.65")
+        self.assertEqual(a.str_val(5), "5.00")
 
     def varcls_modified(self, name):
         var = super().varcls_modified(name)

Orange/data/variable.py

@@ -529,6 +529,7 @@ def __init__(self, name="", number_of_decimals=None, compute_value=None, *, spar
         three, but adjusted at the first call of :obj:`to_val`.
         """
         super().__init__(name, compute_value, sparse=sparse)
+        self._max_round_diff = 0
         self.number_of_decimals = number_of_decimals
 
     @property
@@ -553,6 +554,7 @@ def number_of_decimals(self, x):
             return
 
         self._number_of_decimals = x
+        self._max_round_diff = 10 ** (-x - 6)
         self.adjust_decimals = 0
         if self._number_of_decimals <= MAX_NUM_OF_DECIMALS:
             self._format_str = "%.{}f".format(self.number_of_decimals)
@@ -580,6 +582,10 @@ def repr_val(self, val):
         """
         if isnan(val):
             return "?"
+        if self.format_str != "%g" \
+                and abs(round(val, self._number_of_decimals) - val) \
+                > self._max_round_diff:
+            return f"{val:.{self._number_of_decimals + 2}f}"
         return self._format_str % val
 
     str_val = repr_val
@@ -593,6 +599,7 @@ def copy(self, compute_value=None, *, name=None, **kwargs):
             var.number_of_decimals = number_of_decimals
         else:
             var._number_of_decimals = self._number_of_decimals
+            var._max_round_diff = self._max_round_diff
             var.adjust_decimals = self.adjust_decimals
             var.format_str = self._format_str
         return var