From 2f5952f44cd86682195583a0ffc11ec811632f10 Mon Sep 17 00:00:00 2001
From: Dan Ringwalt <dringw@gmail.com>
Date: Mon, 6 Jul 2015 14:23:47 -0400
Subject: [PATCH] DOC: Clarified PyTables "natural" names

---
 doc/source/io.rst | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/doc/source/io.rst b/doc/source/io.rst
index 7a4318fb02cfc..0c15c91b4690b 100644
--- a/doc/source/io.rst
+++ b/doc/source/io.rst
@@ -3179,9 +3179,10 @@ Notes & Caveats
 .. warning::
 
    ``PyTables`` will show a ``NaturalNameWarning`` if a  column name
-   cannot be used as an attribute selector. Generally identifiers that
-   have spaces, start with numbers, or ``_``, or have ``-`` embedded are not considered
-   *natural*. These types of identifiers cannot be used in a ``where`` clause
+   cannot be used as an attribute selector.
+   *Natural* identifiers contain only letters, numbers, and underscores,
+   and may not begin with a number.
+   Other identifiers cannot be used in a ``where`` clause
    and are generally a bad idea.
 
 DataTypes