ENH: add is_one_of_factory option validator factory

Author: y-p

pandas/core/config.py

@@ -703,6 +703,14 @@ def inner(x):
 
     return inner
 
+def is_one_of_factory(legal_values):
+    def inner(x):
+        from pandas.core.common import pprint_thing as pp
+        if not x in legal_values:
+            pp_values = map(pp, legal_values)
+            raise ValueError("Value must be one of %s" % pp("|".join(pp_values)))
+
+    return inner
 
 # common type validators, for convenience
 # usage: register_option(... , validator = is_int)

pandas/core/config_init.py

@@ -1,6 +1,6 @@
 import pandas.core.config as cf
 from pandas.core.config import (is_int, is_bool, is_text, is_float,
-                                is_instance_factory)
+                                is_instance_factory,is_one_of_factory)
 from pandas.core.format import detect_console_encoding
 
 """