<p dir="auto">right now it fails in list of lists but the error isn't informative.</p>
<p dir="auto">xref: commit <a class="commit-link" data-hovercard-type="commit" data-hovercard-url="https://github.com/pandas-dev/pandas/commit/5a152bdfdd044c6f53c76b361065b1784dc73b61/hovercard" href="https://github.com/pandas-dev/pandas/commit/5a152bdfdd044c6f53c76b361065b1784dc73b61"><tt>5a152bd</tt></a></p>
<h4 dir="auto">A small, complete example of the issue</h4>
<div class="snippet-clipboard-content notranslate position-relative overflow-auto" data-snippet-clipboard-copy-content="a ,a ,a 
1,2,3
4,5,6
7,8,9"><pre class="notranslate"><code class="notranslate">a ,a ,a 
1,2,3
4,5,6
7,8,9
</code></pre></div>
<p dir="auto">note the white space next to the char.</p>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="&gt;&gt;&gt; import pandas
&gt;&gt;&gt; df = pandas.read_table('test.csv', sep=',')
&gt;&gt;&gt; df.columns
Index([u'a ', u'a .1', u'a .2'], dtype='object')"><pre class="notranslate"><span class="pl-c1">&gt;&gt;</span><span class="pl-c1">&gt;</span> <span class="pl-k">import</span> <span class="pl-s1">pandas</span>
<span class="pl-c1">&gt;&gt;</span><span class="pl-c1">&gt;</span> <span class="pl-s1">df</span> <span class="pl-c1">=</span> <span class="pl-s1">pandas</span>.<span class="pl-en">read_table</span>(<span class="pl-s">'test.csv'</span>, <span class="pl-s1">sep</span><span class="pl-c1">=</span><span class="pl-s">','</span>)
<span class="pl-c1">&gt;&gt;</span><span class="pl-c1">&gt;</span> <span class="pl-s1">df</span>.<span class="pl-s1">columns</span>
<span class="pl-v">Index</span>([<span class="pl-s">u'a '</span>, <span class="pl-s">u'a .1'</span>, <span class="pl-s">u'a .2'</span>], <span class="pl-s1">dtype</span><span class="pl-c1">=</span><span class="pl-s">'object'</span>)</pre></div>
<p dir="auto">again, note the white space between the char and the num.</p>
<p dir="auto">A work around previously was to set <code class="notranslate">mangle_dupe_cols</code> to <code class="notranslate">False</code>, manually strip the columns and then clean up the column names. With <code class="notranslate">pandas 0.19.0</code>, <code class="notranslate">mangle_dupe_cols=False</code> raises a <code class="notranslate">ValueError</code>.</p>
<p dir="auto">This issue is more of a question as to what the spec of <code class="notranslate">mangle_dupe_cols</code> is and what a full implementation, mentioned in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="156376368" data-permission-text="Title is private" data-url="https://github.com/pandas-dev/pandas/issues/13262" data-hovercard-type="issue" data-hovercard-url="/pandas-dev/pandas/issues/13262/hovercard" href="https://github.com/pandas-dev/pandas/issues/13262">#13262</a> , desires/is going to be.</p>
<h4 dir="auto">Expected Output</h4>
<div class="highlight highlight-source-python notranslate position-relative overflow-auto" dir="auto" data-snippet-clipboard-copy-content="Index([u'a', u'a.1', u'a.2'], dtype='object')"><pre class="notranslate"><span class="pl-v">Index</span>([<span class="pl-s">u'a'</span>, <span class="pl-s">u'a.1'</span>, <span class="pl-s">u'a.2'</span>], <span class="pl-s1">dtype</span><span class="pl-c1">=</span><span class="pl-s">'object'</span>)</pre></div>
<h4 dir="auto">Output of <code class="notranslate">pd.show_versions()</code></h4>
<details>
## INSTALLED VERSIONS
<p dir="auto">commit: None<br>
python: 2.7.11.final.0<br>
python-bits: 64<br>
OS: Darwin<br>
OS-release: 15.6.0<br>
machine: x86_64<br>
processor: i386<br>
byteorder: little<br>
LC_ALL: en_US.UTF-8<br>
LANG: en_US.UTF-8<br>
LOCALE: None.None</p>
<p dir="auto">pandas: 0.19.0<br>
nose: 1.3.7<br>
pip: 8.1.2<br>
setuptools: 23.1.0<br>
Cython: 0.24<br>
numpy: 1.10.4<br>
scipy: None<br>
statsmodels: None<br>
xarray: None<br>
IPython: 5.1.0<br>
sphinx: 1.4.1<br>
patsy: None<br>
dateutil: 2.5.2<br>
pytz: 2016.3<br>
blosc: None<br>
bottleneck: None<br>
tables: None<br>
numexpr: None<br>
matplotlib: None<br>
openpyxl: 2.4.0<br>
xlrd: 1.0.0<br>
xlwt: None<br>
xlsxwriter: None<br>
lxml: 3.6.0<br>
bs4: 4.4.1<br>
html5lib: 0.999<br>
httplib2: None<br>
apiclient: None<br>
sqlalchemy: None<br>
pymysql: None<br>
psycopg2: None<br>
jinja2: None<br>
boto: None<br>
pandas_datareader: None</p>
</details>