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Merge a list of dataframes to create one dataframe

Given a list of pandas dataframes, we have to merge them in one dataframe. By Pranit Sharma Last updated : September 19, 2023

Pandas is a special tool that allows us to perform complex manipulations of data effectively and efficiently. Inside pandas, we mostly deal with a dataset in the form of DataFrame. DataFrames are 2-dimensional data structures in pandas. DataFrames consist of rows, columns, and data.

Problem statement

We are given a list of DataFrames, and we need to perform an operation such that all the DataFrames are merged together and result in a single DataFrame.

How to merge a list of dataframes to one dataframe?

For this purpose, we will first create multiple DataFrames with one common column, and then we will merge them using DataFrame.merge() method.

Here is the syntax of the DataFrame.merge() method:

DataFrame.merge(
    right, 
    how='inner', 
    on=None, 
    left_on=None, 
    right_on=None, 
    left_index=False, 
    right_index=False, 
    sort=False, 
    suffixes=('_x', '_y'), 
    copy=True, 
    indicator=False, 
    validate=None
    )

Let us understand with the help of an example,

Python program to merge a list of dataframes to create one dataframe

# Importing pandas package
import pandas as pd

# Creating DataFrames
df1 = pd.DataFrame({'id':[1,2,3,4],'Name':['Ram','Mohan','Prem','Lal']})
df2 = pd.DataFrame({'id':[1,2,3,4],'Name':['Shyam','Rohan','Priyanka','Lalit']})
df3 = pd.DataFrame({'id':[1,2,3,4],'Name':['Seeta','Pawan','Hema','Amit']})

# Display the DataFrame
print("Original DataFrame 1:\n",df1,"\n")
print("Original DataFrame 1:\n",df1,"\n")
print("Original DataFrame 1:\n",df1,"\n")

# encapsulating all the dfs in a list
df_list = [df1,df2,df3]

# Merging the dataframes
df = [df.set_index('id') for df in df_list]

# Display modified DataFrames
print("Concerted DataFrames:\n",pd.concat(df, axis=1))

Output

The output of the above program is:

Reference:

• pandas.DataFrame.merge()

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