Merge pull request astanin#51 from djw8605/decimal-align-commas

Recognize numbers with comma separators

Author: astanin

tabulate.py

@@ -595,8 +595,16 @@ def _isnumber(string):
     False
     >>> _isnumber("inf")
     True
+    >>> _isnumber("1,234.56")
+    True
+    >>> _isnumber("1,234,578.0")
+    True
     """
-    if not _isconvertible(float, string):
+    if isinstance(string, (_text_type)) and "," in string and (
+        _isconvertible(float, string.replace(",",""))
+    ):
+        return True
+    elif not _isconvertible(float, string):
         return False
     elif isinstance(string, (_text_type, _binary_type)) and (
         math.isinf(float(string)) or math.isnan(float(string))