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May 20, 2014
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Update indexing.rst #7188

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10 changes: 7 additions & 3 deletions doc/source/indexing.rst
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Expand Up @@ -206,15 +206,19 @@ as an attribute:
dfa.A
panel.one

Setting is allowed as well
You can use attribute access to modify an existing element of a Series or column of a DataFrame, but be careful;
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maybe move these couple of lines to an actual .. warning:: see below

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I considered that but thought this was enough of a gotcha that I wanted to
keep the warning right there with the problematic example.

But I am willing to be overruled.

On Tue, May 20, 2014 at 3:01 PM, jreback [email protected] wrote:

In doc/source/indexing.rst:

@@ -206,15 +206,19 @@ as an attribute:
dfa.A
panel.one

-Setting is allowed as well
+You can use attribute access to modify an existing element of a Series or column of a DataFrame, but be careful;

maybe move these couple of lines to an actual .. warning:: see below

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/7188/files#r12861818
.

if you try to use attribute access to create a new column, it fails silently, creating a new attribute rather than a
new column.

.. ipython:: python

sa.a = 5
sa
dfa.A = list(range(len(dfa.index)))
dfa.A = list(range(len(dfa.index))) # ok if A already exists
dfa

dfa['A'] = list(range(len(dfa.index))) # use this form to create a new column
dfa

.. warning::

- You can use this access only if the index element is a valid python identifier, e.g. ``s.1`` is not allowed.
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