create an empty dataframe

newDF = pd.DataFrame() #creates a new dataframe that's empty
newDF = newDF.append(oldDF, ignore_index = True) # ignoring index is optional
# try printing some data from newDF
print newDF.head() #again optional 

import pandas as pd

col_names =  ['A', 'B', 'C']
my_df  = pd.DataFrame(columns = col_names)
my_df