format negative scientific notation correctly

Author: adrianmolzon

bayes_opt/logger.py

@@ -75,16 +75,38 @@ def _format_number(self, x: float) -> str:
         -------
         A stringified, formatted version of `x`.
         """
-        if isinstance(x, int):
-            s = f"{x:<{self._default_cell_size}}"
+        if abs(x) > 1e7 - 1:
+            s = f"{x:.5e}"
         else:
-            s = f"{x:<{self._default_cell_size}.{self._default_precision}}"
+            s = str(x)
 
         if len(s) > self._default_cell_size:
+            # Convert to str representation of scientific notation
+            result = ""
+            width = self._default_cell_size
+            # Keep negative sign, exponent, and as many decimal places as possible
+            if "-" in s:
+                result += "-"
+                width -= 1
+                s = s[1:]
+            if "e" in s:
+                e_pos = s.find("e")
+                end = s[e_pos:]
+                width -= len(end)
             if "." in s:
-                return s[: self._default_cell_size]
-            return s[: self._default_cell_size - 3] + "..."
-        return s
+                dot_pos = s.find(".") + 1
+                result += s[:dot_pos]
+                width -= dot_pos
+                if width > 0:
+                    result += s[dot_pos : dot_pos + width]
+            else:
+                result += s[:width]
+            if "e" in s:
+                result += end
+            result = result.ljust(self._default_cell_size)
+        else:
+            result = s.ljust(self._default_cell_size)
+        return result
 
     def _format_bool(self, x: bool) -> str:
         """Format a boolean.

tests/test_logger.py

@@ -67,12 +67,37 @@ def test_format_number():
     long_int = 12345678901234
     formatted = logger._format_number(long_int)
     assert len(formatted) == logger._default_cell_size
-    assert "..." in formatted
+    assert formatted == "1.234e+13"
 
     # Test long float truncation
     long_float = 1234.5678901234
     formatted = logger._format_number(long_float)
     assert len(formatted) == logger._default_cell_size
+    assert formatted == "1234.5678"
+
+    # Test negative long float truncation
+    long_float = -1234.5678901234
+    formatted = logger._format_number(long_float)
+    assert len(formatted) == logger._default_cell_size
+    assert formatted == "-1234.567"
+
+    # Test scientific notation truncation
+    sci_float = 12345678901234.5678901234
+    formatted = logger._format_number(sci_float)
+    assert len(formatted) == logger._default_cell_size
+    assert formatted == "1.234e+13"
+
+    # Test negative scientific notation truncation
+    sci_float = -12345678901234.5678901234
+    formatted = logger._format_number(sci_float)
+    assert len(formatted) == logger._default_cell_size
+    assert formatted == "-1.23e+13"
+
+    # Test long scientific notation truncation
+    sci_float = -12345678901234.534e132
+    formatted = logger._format_number(sci_float)
+    assert len(formatted) == logger._default_cell_size
+    assert formatted == "-1.2e+145"
 
 
 def test_format_bool():