Convert multiple columns to one column
<p>I'm looking to merge multiple columns to one column.</p>

<p>Here's my current dataset :</p>

<pre><code>Column A  Column B   Column C 
    a1       b1        c1 
    b2       a2        e2 
</code></pre>

<p>I am looking for the following as output</p>

<pre><code>Column D  
  a1
  b1
  c1
  b2 
  a2
  e2
</code></pre>

<p>Is this possible ? Using R or Python ?</p>

<p>With the data that you provided, in the format you provided, you could do this with:</p>

<pre><code>data.frame(ColumnD=c(t(df)))

  ColumnD
1      a1
2      b1
3      c1
4      b2
5      a2
6      e2
</code></pre>

<p>We transpose the data, then combine it.</p>

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