Pandas DataFrame に複数の列を効率的に追加するにはどうすればよいですか?

df[['column_new_1', 'column_new_2', 'column_new_3']] = [np.nan, 'dogs', 3]

df['column_new_1'], df['column_new_2'], df['column_new_3'] = np.nan, 'dogs', 3

df[['column_new_1', 'column_new_2', 'column_new_3']] = pd.DataFrame([[np.nan, 'dogs', 3]], index=df.index)

df = pd.concat(
    [
        df,
        pd.DataFrame(
            [[np.nan, 'dogs', 3]], 
            index=df.index, 
            columns=['column_new_1', 'column_new_2', 'column_new_3']
        )
    ], axis=1
)

df = df.join(pd.DataFrame(
    [[np.nan, 'dogs', 3]], 
    index=df.index, 
    columns=['column_new_1', 'column_new_2', 'column_new_3']
))

df = df.join(pd.DataFrame(
    {
        'column_new_1': np.nan,
        'column_new_2': 'dogs',
        'column_new_3': 3
    }, index=df.index
))

df = df.assign(column_new_1=np.nan, column_new_2='dogs', column_new_3=3)

new_cols = ['column_new_1', 'column_new_2', 'column_new_3']
new_vals = [np.nan, 'dogs', 3]
df = df.reindex(columns=df.columns.tolist() + new_cols)  # add empty cols
df[new_cols] = new_vals  # multi-column assignment works for existing cols

df['column_new_1'] = np.nan
df['column_new_2'] = 'dogs'
df['column_new_3'] = 3