title: Choose type while merging pandas dataframes
body: <pre class="lang-none prettyprint-override"><code>/data/anaconda3/lib/python3.5/site-packages/pandas/core/reshpae/merge.py:963: UserWarning: You are merging on int and float columns where the float values are not equal to their int representation 'representation', UserWarning)
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  <p>I was merging multiple dataframes and got the above message. I was able to find out which columns have different dtypes and changed one. This time, there were only two columns, but I can't deal with this kind of situation every time. (Sometimes, I get more than 10 tables with more than 20 columns each!)</p>
  
  <p>How can I <code>pd.merge()</code> while choosing dtypes when they are conflicted? (Obviously, I should go through the data and give a little touch before merging right away. Just wondering if there is a more efficient way to do things.)</p>