merging 2 dataframes vertically
<p>I have 2 dataframes that have 2 columns each (same column names). I want to merge them vertically to end up having a new dataframe.</p>

<p>When doing  </p>

<pre><code>newdf = df.merge(df1,how='left',on=['Col1','Col2'])
</code></pre>

<p>The new df has only the rows from <code>df</code> and none of the rows from <code>df1</code>. Any reasons why this might happen?</p>

<pre><code>Col1    Col2
asd     1232
cac     2324
.....
</code></pre>

<p>and the <code>df1</code> is:</p>

<pre><code>Col1    Col2
afaf    1213
asas    4353
</code></pre>

<p>The new dataframe <code>newdf</code> should be:</p>

<pre><code>Col1   Col2
asd     1232
cac     2324
afaf    1213
asas    4353
</code></pre>