How to add multiple columns to pandas dataframe in one assignment?
<p>I'm new to pandas and trying to figure out how to add multiple columns to pandas simultaneously.  Any help here is appreciated.  Ideally I would like to do this in one step rather than multiple repeated steps...</p>

<pre><code>import pandas as pd

df = {'col_1': [0, 1, 2, 3],
        'col_2': [4, 5, 6, 7]}
df = pd.DataFrame(df)

df[[ 'column_new_1', 'column_new_2','column_new_3']] = [np.nan, 'dogs',3]  #thought this would work here...
</code></pre>