Merge pull request #12045 from Lewn/patch-1

NelleV · web-flow · commit 0753e59f4b7e · 2018-09-07T11:22:05.000-07:00
Fix 999.9... edge case in ticker.EngFormatter for negative numbers
diff --git a/lib/matplotlib/tests/test_ticker.py b/lib/matplotlib/tests/test_ticker.py
@@ -655,6 +655,7 @@ class TestEngFormatter(object):
         (1.23456789, ('1.23457', '1', '1.23')),
         (999.9, ('999.9', '1 k', '999.90')),  # places=0: corner-case rounding
         (999.9999, ('1 k', '1 k', '1.00 k')),  # corner-case roudning for all
+        (-999.9999, ('-1 k', '-1 k', '-1.00 k')),  # negative corner-case
         (1000, ('1 k', '1 k', '1.00 k')),
         (1001, ('1.001 k', '1 k', '1.00 k')),
         (100001, ('100.001 k', '100 k', '100.00 k')),
diff --git a/lib/matplotlib/ticker.py b/lib/matplotlib/ticker.py
@@ -1268,7 +1268,8 @@ def format_eng(self, num):
         # Taking care of the cases like 999.9..., which may be rounded to 1000
         # instead of 1 k.  Beware of the corner case of values that are beyond
         # the range of SI prefixes (i.e. > 'Y').
-        if float(format(mant, fmt)) >= 1000 and pow10 < max(self.ENG_PREFIXES):
+        if (abs(float(format(mant, fmt))) >= 1000
+                   and pow10 < max(self.ENG_PREFIXES)):
             mant /= 1000
             pow10 += 3
 
