explode方法
df['bucket_type'] = df.apply(lambda x: list(zip(x['XVA'],x['XVARisk'])),axis=1)
df = df.explode('bucket_type')
dfflat = dfcomb.apply(pd.Series.explode)
df['bucket_type'] = df.apply(lambda x: list(zip(x['XVA'],x['XVARisk'])),axis=1)
df = df.explode('bucket_type')
dfflat = dfcomb.apply(pd.Series.explode)