In this article, we will discuss how to merge the two dataframes with different lengths in Pandas. It can be done using the merge() method.
Syntax:
DataFrame.merge(parameters)
Below are some examples that depict how to merge data frames of different lengths using the above method:
Example 1:
Below is a program to merge two student data frames of different lengths.
Python3
# importing pandas module import pandas as pd
# create a list that contains # student id of subject 1 list1 = [7058, 7059, 7075, 7076]
# create a list that contains # student id of subject 2 list2 = [7058, 7059, 7012, 7075, 7076]
# create a list that contains # student names of subject 1 list11 = ["Sravan", "Jyothika", "Deepika",
"Kyathi"]
# create a list that contains # student names of subject 2 list22 = ["Sravan", "Jyothika", "Salma",
"Deepika", "Kyathi"]
# pass list1 and list11 to the # dataframe1 dataframe1 = pd.DataFrame(
{"Student ID": list1, "Student Name": list11})
print('First data frame:')
display(dataframe1) # pass list2 and list22 to the # dataframe1 dataframe2 = pd.DataFrame(
{"Student ID": list2, "Student Name": list22})
print('Second data frame:')
display(dataframe2) # apply merge function to merge the # two dataframes mergedf = dataframe2.merge(dataframe1, how='left')
print('Merged data frame:')
display(mergedf) |
Output:
Example 2:
Here is another program to merge one data frame of length 4 and another dataframe of length 9.
Python3
# importing pandas module import pandas as pd
# create a list that contains # student id of subject 1 list1 = [7058, 7059, 7075, 7076]
# create a list that contains # student id of subject 2 list2 = [7058, 7059, 7012, 7075, 7076,
7034, 7046, 7036, 7015]
# create a list that contains # student names of subject 1 list11 = ["Sravan", "Jyothika", "Deepika",
"Kyathi"]
# create a list that contains # student names of subject 2 list22 = ["Sravan", "Jyothika", "salma",
"Deepika", "Kyathi", "meghana",
"pranathi", "bhanu", "keshav"]
# pass list1 and list11 to the # dataframe1 dataframe1 = pd.DataFrame(
{"Student ID": list1, "Student Name": list11})
print('First data frame:')
display(dataframe1) # pass list2 and list22 to the # dataframe1 dataframe2 = pd.DataFrame(
{"Student ID": list2, "Student Name": list22})
print('Second data frame:')
display(dataframe2) # apply merge function to merge # the two dataframes mergedf = dataframe2.merge(dataframe1, how='inner')
print('Merged data frame:')
display(mergedf) |
Output: