FIX: Remove trailing zeros from offset significand

Fix regression in 3.4.0 introduced by b5fb685 (matplotlib#18506).

Author: StefRe

lib/matplotlib/tests/test_ticker.py

@@ -500,6 +500,13 @@ class TestScalarFormatter:
         [12.3, "12.300"],
     ]
 
+    format_data = [
+        (.1, "1e-1"),
+        (.11, "1.1e-1"),
+        (1e8, "1e8"),
+        (1.1e8, "1.1e8"),
+    ]
+
     @pytest.mark.parametrize('unicode_minus, result',
                              [(True, "\N{MINUS SIGN}1"), (False, "-1")])
     def test_unicode_minus(self, unicode_minus, result):
@@ -561,6 +568,12 @@ def test_scilimits(self, sci_type, scilimits, lim, orderOfMag, fewticks):
         tmp_form.set_locs(ax.yaxis.get_majorticklocs())
         assert orderOfMag == tmp_form.orderOfMagnitude
 
+    @pytest.mark.parametrize('value, expected', format_data)
+    def test_format_data(self, value, expected):
+        mpl.rcParams['axes.unicode_minus'] = False
+        sf = mticker.ScalarFormatter()
+        assert sf.format_data(value) == expected
+
     @pytest.mark.parametrize('data, expected', cursor_data)
     def test_cursor_precision(self, data, expected):
         fig, ax = plt.subplots()

lib/matplotlib/ticker.py

@@ -664,7 +664,7 @@ def format_data(self, value):
         s = round(value / 10**e, 10)
         exponent = self._format_maybe_minus_and_locale("%d", e)
         significand = self._format_maybe_minus_and_locale(
-            "%d" if s % 1 == 0 else "%1.10f", s)
+            "%d" if s % 1 == 0 else "%1.10g", s)
         if e == 0:
             return significand
         elif self._useMathText or self._usetex: