Merge & Join List of pandas DataFrames in Python (Example Code)

import pandas as pd                       # Import pandas library to Python

import pandas as pd # Import pandas library to Python

df1 = pd.DataFrame({"ID":range(1, 6),     # Construct three DataFrames
                    "A":range(11, 16),
                    "B":["g", "x", "g", "d", "f"]})
print(df1)
#    ID   A  B
# 0   1  11  g
# 1   2  12  x
# 2   3  13  g
# 3   4  14  d
# 4   5  15  f

df1 = pd.DataFrame({"ID":range(1, 6), # Construct three DataFrames "A":range(11, 16), "B":["g", "x", "g", "d", "f"]}) print(df1) # ID A B # 0 1 11 g # 1 2 12 x # 2 3 13 g # 3 4 14 d # 4 5 15 f

df2 = pd.DataFrame({"ID":range(3, 8),
                    "C":["a", "y", "s", "x", "a"],
                    "D":range(12, 2, - 2)})
print(df2)
#    ID  C   D
# 0   3  a  12
# 1   4  y  10
# 2   5  s   8
# 3   6  x   6
# 4   7  a   4

df2 = pd.DataFrame({"ID":range(3, 8), "C":["a", "y", "s", "x", "a"], "D":range(12, 2, - 2)}) print(df2) # ID C D # 0 3 a 12 # 1 4 y 10 # 2 5 s 8 # 3 6 x 6 # 4 7 a 4

df3 = pd.DataFrame({"ID":range(2, 10),
                    "E":range(10, 2, - 1),
                    "F":range(9, 1, - 1)})
print(df3)
#    ID   E  F
# 0   2  10  9
# 1   3   9  8
# 2   4   8  7
# 3   5   7  6
# 4   6   6  5
# 5   7   5  4
# 6   8   4  3
# 7   9   3  2

df3 = pd.DataFrame({"ID":range(2, 10), "E":range(10, 2, - 1), "F":range(9, 1, - 1)}) print(df3) # ID E F # 0 2 10 9 # 1 3 9 8 # 2 4 8 7 # 3 5 7 6 # 4 6 6 5 # 5 7 5 4 # 6 8 4 3 # 7 9 3 2

my_list = [df1, df2, df3]                 # Construct list object

my_list = [df1, df2, df3] # Construct list object

from functools import reduce              # Loading reduce function

from functools import reduce # Loading reduce function

df_joined = reduce(lambda left, right:    # Merge multiple DataFrames in list
                    pd.merge(left , right,
                             on = ["ID"]),
                    my_list)
print(df_joined)
#    ID   A  B  C   D  E  F
# 0   3  13  g  a  12  9  8
# 1   4  14  d  y  10  8  7
# 2   5  15  f  s   8  7  6

df_joined = reduce(lambda left, right: # Merge multiple DataFrames in list pd.merge(left , right, on = ["ID"]), my_list) print(df_joined) # ID A B C D E F # 0 3 13 g a 12 9 8 # 1 4 14 d y 10 8 7 # 2 5 15 f s 8 7 6