pd.merge on two columns code example

Example 1: pd merge on multiple columns

new_df = pd.merge(A_df, B_df,  how='left', left_on=['A_c1','c2'], right_on = ['B_c1','c2'])

Example 2: combining 2 dataframes pandas

df_3 = pd.concat([df_1, df_2])

Example 3: pandas merge multiple dataframes

import pandas as pd
from functools import reduce

# compile the list of dataframes you want to merge
data_frames = [df1, df2, df3]
df_merged = reduce(lambda  left,right: pd.merge(left,right,on=['key_col'],
                                            how='outer'), data_frames)

Example 4: python inner join based on two columns

df  = pd.merge(left=df1, right=df2, on=['var_1', 'var_2'], how='inner']