pandas concat arbirary number of dataframes code example
Example 1: join on column pandas
# df1 as main df and use the feild from df2 and map it into df1
df1.merge(df2,on='columnName',how='left')
Example 2: how to append a dataframe to another dataframe in pandas
# all_res is list of DataFrames : [ dataframe, dataframe, ... ]
df_res = pd.concat(all_res)