title: Select columns in pandas dataframe by value in rows
body: <p>I have a <code>pandas.DataFrame</code> with too much columns. I want to select all columns with values in rows equals to <code>0</code> and <code>1</code>. Type of all columns is <code>int64</code> and I can't select they by <code>object</code> or other type. How can I do this?</p>