Add multiple empty columns to pandas DataFrame

Question

How do I add multiple empty columns to a DataFrame from a list?

I can do:

    df["B"] = N         


        

Answer 1

Summary of alternative solutions:

columns_add = ['a', 'b', 'c']

1. for loop:

   for newcol in columns_add:
       df[newcol]= None
   

2. dict method:

   df.assign(**dict([(_,None) for _ in columns_add]))
   

3. tuple assignment:

   df['a'], df['b'], df['c'] = None, None, None