pandas merge multiple dataframes

df_col = pd.concat([df1,df2], axis=1)

df_col

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

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

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)

# Joins with another DataFrame

df.join(df2, df.name == df2.name, 'outer').select(
  df.name, df2.height).collect()
# [Row(name=None, height=80), Row(name=u'Bob', height=85), Row(
#   name=u'Alice', height=None)]

df.join(df2, 'name', 'outer').select('name', 'height').collect()
# [Row(name=u'Tom', height=80), Row(name=u'Bob', height=85), Row(
#   name=u'Alice', height=None)]

cond = [df.name == df3.name, df.age == df3.age]
df.join(df3, cond, 'outer').select(df.name, df3.age).collect()
# [Row(name=u'Alice', age=2), Row(name=u'Bob', age=5)]

df.join(df2, 'name').select(df.name, df2.height).collect()
# Row(name=u'Bob', height=85)]

df.join(df4, ['name', 'age']).select(df.name, df.age).collect()
# [Row(name=u'Bob', age=5)]

df_merge_col = pd.merge(df_row, df3, on='id')

df_merge_col

# Pandas for Python

df['col1 & col2'] = df['col1']+df['col2']

#Output
#col1	col2	col1 & col2
#A1		A2		A1A2
#B1		B2		B1B2

df = DataFrame({'var_1':['a','b','c'], 'var_2':[1, 2, 3], 'var_3':['apple', 'banana', 'pear']})
cols = ['var_1', 'var_2']    # Set columns to combine
df['combined'] = df[cols].apply(lambda row: ', '.join(row.values.astype(str)), axis=1)

# Define which column is index
df_i = df.set_index('combined') 

# Set the index to None
df_i.index.names = [None] 

df["period"] = df["Year"] + df["quarter"]

# Python program to merge 
# dataframes using Panda 
  
# Dataframe created 
left = pd.DataFrame({'Key': ['K0', 'K1', 'K2', 'K3'], 
                    'A': ['A0', 'A1', 'A2', 'A3'], 
                    'B': ['B0', 'B1', 'B2', 'B3']}) 
  
right = pd.DataFrame({'Key': ['K0', 'K1', 'K2', 'K3'], 
                      'C': ['C0', 'C1', 'C2', 'C3'], 
                      'D': ['D0', 'D1', 'D2', 'D3']}) 
                        
# Merging the dataframes                       
pd.merge(left, right, how ='inner', on ='Key')