merge csv with pandas

#!/usr/bin/env python3
import pandas as pd
f1 = pd.read_csv(
    'file1.csv',
    header=0,
    names=['date','ringo','mikan','banana'])
f2 = pd.read_csv(
    'file2.csv',
    header=0,
    names=['date','chicken','beef','pork'])
f3 = f1.merge(f2, how='outer').sort_values(by='date')
f3.to_csv(
    'file3.csv',
    header=['','りんご','みかん','バナナ','鶏肉','牛肉','豚肉'],
    index=None,
    float_format='%.0f',
    na_rep='#N/A')