How to Merge 2 Dataframes in Python - Part 2

Python Pandas Merge two dataframes 2020. Pandas Concat - Learn how to merge multiple data frames together using LEFT, INNER, FULL and CROSS join in Python. I will be providing the raw data & the code in case you want to try this yourself (best way of learning python).

Data Analytics Course Link:

Part 1 link:

Tutorial Overview:
Part 1:
1) Loading CSV Data into Pandas df
2) Left Join

Part 2:
3) Inner Join
4) Full Join
5) Cross Join
6) Right Join - Why bother?
7) Union All / Concat

Pandas tutorial link:

How to download and install Python through Anaconda:

Download Code and Raw Data:

Yiannis Pitsillides on Social Media:

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Python Pandas Merge two dataframes 2020 - Part 2
Python Pandas Merge two dataframes 2020
Python Pandas Merge two dataframes

[nikitalad]

Found the exact thing what I wanted after searching internet for almost 10 hours. You are an angel.

[YiannisPi]

Hey everyone! Hope you enjoyed this tutorial! Please let me know in the comments below! Thanks!

[harikrishna-harrypth]

Your tutorials are absolutely amazing!!!! Thanks a lot!!

[michaelbachman]

I really appreciate your thorough explanations! You state that there is no function for a cross-join; but doesn't the 'pd.melt' method result in the same outcome as a Cross-join? If not, can you walk thorough the differences? Thank you!

[LoraLameh]

amazing explanation the best so far !!

[GodX]

Hi, thank for your great videos. If we have many file .csv such as data of stocks, now I would like to take data of each column of each .csv (such as close price columns of each stocks price) to make index of sector for analysising sector, would you please help me how to do it 🙏🙏

[bharatapar]

Hi,
if there is a duplicate record in second dataframe (like 'Houston' in below case) and i want to print only one Houston in the final output after doing outer join (as only one Houston is present in first data frame) but its not happening and in the final output after outer join, Houston is repeating in left dataframe also as mentioned below. Pl see the below test data. Pl help.
DataFrame -1

ID1 City Population 
1 CHICAGO 3000 
5 HOUSTON 14000 
7 NEW JERSEY 18000 
7 NEW JERSEY 20000
DataFrame -2

ID2 City POPULATION 
4 ARIZONA 2000 
5 HOUSTON 3000 
5 HOUSTON 4000 
5 HOUSTON 5000 
7 NEW JERSEY 3000 
8 MICHIGAN 4000
det = pd.merge(df1, df2, left_on=['ID1'], right_on=['ID2'], how='outer', indicator='indicator', suffixes=('_A', '_B'))
Actual Output:

ID1 City_A Population ID2 City_B POPULATION indicator
0 1.0 CHICAGO 3000.0 NaN N. aN NaN left_only
1 5.0 HOUSTON 14000.0 5.0 HOUSTON 3000.0 both
1 5.0 HOUSTON 14000.0 5.0 HOUSTON 4000.0 both
1 5.0 HOUSTON 14000.0 5.0 HOUSTON 5000.0 both
4 7.0 NEW JERSEY 18000.0 7.0 NEW JERSEY 3000.0 both
5 7.0 NEW JERSEY 20000.0 7.0 NEW JERSEY 3000.0 both
6 NaN NaN NaN 4.0 ARIZONA 2000.0 right_only
7 NaN NaN NaN 8.0 MICHIGAN 4000.0 right_only
Expected Output:

ID1 City_A Population ID2 City_B POPULATION indicator
0 1.0 CHICAGO 3000.0 NaN NaN NaN left_only
1 5.0 HOUSTON 14000.0 5.0 HOUSTON 3000.0 both
2 5.0 NaN NaN NaN HOUSTON 4000.0 both
3 5.0 NaN NaN NaN HOUSTON 5000.0 both
4 7.0 NEW JERSEY 18000.0 7.0 NEW JERSEY 3000.0 both
5 7.0 NEW JERSEY 20000.0 7.0 NaN 0 both
6 NaN NaN NaN 4.0 ARIZONA 2000.0 right_only
7 NaN NaN NaN 8.0 MICHIGAN 4000.0 right_only

[raunakmaitra]

I'm getting a duplication problem, after running the codes