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New to the Python world and I'm working through a problem where I need to pull a value for the largest index value for each year. Will provide a table example and explain further

Year Index D_Value
2010 13 85
2010 14 92
2010 15 76
2011 9 68
2011 10 73
2012 100 94
2012 101 89

So, the desired output would look like this:

Year Index D_Value
2010 15 76
2011 10 73
2012 101 89

I've tried researching how to apply max() and .loc() functions, however, I'm not sure what the optimal approach is for this scenario. Any help would be greatly appreciated. I've also included the below code to generate the test table.

import pandas as pd

data = {'Year':[2010,2010,2010,2011,2011,2012,2012],'Index':[13,14,15,9,10,100,101],'D_Value':[85,92,76,68,73,94,89]}

df = pd.DataFrame(data)

print(df)
2020db9
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1 Answers1

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You can use groupby + rank

df['Rank'] = df.groupby(by='Year')['Index'].rank(ascending=False)
print(df[df['Rank'] ==1])
dkantor
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