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

I'd concat using a DataFrame:

In [23]:
df = pd.DataFrame(columns=['A'])
df

Out[23]:
Empty DataFrame
Columns: [A]
Index: []

In [24]:    
pd.concat([df,pd.DataFrame(columns=list('BCD'))])

Out[24]:
Empty DataFrame
Columns: [A, B, C, D]
Index: []

So by passing a list containing your original df, and a new one with the columns you wish to add, this will return a new df with the additional columns.

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Caveat: See the discussion of performance in the other answers and/or the comment discussions. reindex may be preferable where performance is critical.