How to take column of dataframe in pandas : <p>now I have this dataframe:</p>

<pre><code>      A    B    C
0     m   1    b
1     n   4    a
2     p   3    c
3     o   4    d
4     k   6    e
</code></pre>

<p>so,How I can get <strong>n,p,k</strong> in column。as follow:</p>

<pre><code>      A    B    C
0     n   4    a
1     p   3    c
2     k   6    e
</code></pre>

<p>thanks</p>
