Pandas merging two dataframes with different number of multiindices











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Welcome, I have a simple question, to which I haven't found a solution.



I have two dataframes df1 and df2:





  • df1 contains several columns and a multiindex as year-month-week


  • df2 contains the multiindex year-week with only one column in the df.




I would like to create an inner join of df1 and df2, joining on 'year' and 'week'.





I have tried to do the following:



df1['newcol'] = df1.index.get_level_values(2).map(lambda x: df2.newcol[x])


Which only joins on month (or year?), is there any way to expand it so that the merge is actually right?



Thanks in advance!



df1



df2










share|improve this question




















  • 2




    Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
    – jpp
    Nov 22 at 15:10






  • 2




    Show us some sample of the datasets. Refer to the guide on how to add code snippets.
    – Shiv_90
    Nov 22 at 15:11










  • I added some pictures to represent the dataset, i hope it helps!
    – acronis011
    Nov 22 at 15:22










  • We can't copy/paste pictures into python :D
    – user3471881
    Nov 22 at 15:32






  • 1




    Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
    – maow
    Nov 22 at 15:38

















up vote
0
down vote

favorite












Welcome, I have a simple question, to which I haven't found a solution.



I have two dataframes df1 and df2:





  • df1 contains several columns and a multiindex as year-month-week


  • df2 contains the multiindex year-week with only one column in the df.




I would like to create an inner join of df1 and df2, joining on 'year' and 'week'.





I have tried to do the following:



df1['newcol'] = df1.index.get_level_values(2).map(lambda x: df2.newcol[x])


Which only joins on month (or year?), is there any way to expand it so that the merge is actually right?



Thanks in advance!



df1



df2










share|improve this question




















  • 2




    Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
    – jpp
    Nov 22 at 15:10






  • 2




    Show us some sample of the datasets. Refer to the guide on how to add code snippets.
    – Shiv_90
    Nov 22 at 15:11










  • I added some pictures to represent the dataset, i hope it helps!
    – acronis011
    Nov 22 at 15:22










  • We can't copy/paste pictures into python :D
    – user3471881
    Nov 22 at 15:32






  • 1




    Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
    – maow
    Nov 22 at 15:38















up vote
0
down vote

favorite









up vote
0
down vote

favorite











Welcome, I have a simple question, to which I haven't found a solution.



I have two dataframes df1 and df2:





  • df1 contains several columns and a multiindex as year-month-week


  • df2 contains the multiindex year-week with only one column in the df.




I would like to create an inner join of df1 and df2, joining on 'year' and 'week'.





I have tried to do the following:



df1['newcol'] = df1.index.get_level_values(2).map(lambda x: df2.newcol[x])


Which only joins on month (or year?), is there any way to expand it so that the merge is actually right?



Thanks in advance!



df1



df2










share|improve this question















Welcome, I have a simple question, to which I haven't found a solution.



I have two dataframes df1 and df2:





  • df1 contains several columns and a multiindex as year-month-week


  • df2 contains the multiindex year-week with only one column in the df.




I would like to create an inner join of df1 and df2, joining on 'year' and 'week'.





I have tried to do the following:



df1['newcol'] = df1.index.get_level_values(2).map(lambda x: df2.newcol[x])


Which only joins on month (or year?), is there any way to expand it so that the merge is actually right?



Thanks in advance!



df1



df2







python pandas dataframe






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 22 at 15:20

























asked Nov 22 at 15:09









acronis011

33




33








  • 2




    Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
    – jpp
    Nov 22 at 15:10






  • 2




    Show us some sample of the datasets. Refer to the guide on how to add code snippets.
    – Shiv_90
    Nov 22 at 15:11










  • I added some pictures to represent the dataset, i hope it helps!
    – acronis011
    Nov 22 at 15:22










  • We can't copy/paste pictures into python :D
    – user3471881
    Nov 22 at 15:32






  • 1




    Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
    – maow
    Nov 22 at 15:38
















  • 2




    Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
    – jpp
    Nov 22 at 15:10






  • 2




    Show us some sample of the datasets. Refer to the guide on how to add code snippets.
    – Shiv_90
    Nov 22 at 15:11










  • I added some pictures to represent the dataset, i hope it helps!
    – acronis011
    Nov 22 at 15:22










  • We can't copy/paste pictures into python :D
    – user3471881
    Nov 22 at 15:32






  • 1




    Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
    – maow
    Nov 22 at 15:38










2




2




Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
– jpp
Nov 22 at 15:10




Can you provide a sample dataframe via a Minimal, Complete, and Verifiable example.
– jpp
Nov 22 at 15:10




2




2




Show us some sample of the datasets. Refer to the guide on how to add code snippets.
– Shiv_90
Nov 22 at 15:11




Show us some sample of the datasets. Refer to the guide on how to add code snippets.
– Shiv_90
Nov 22 at 15:11












I added some pictures to represent the dataset, i hope it helps!
– acronis011
Nov 22 at 15:22




I added some pictures to represent the dataset, i hope it helps!
– acronis011
Nov 22 at 15:22












We can't copy/paste pictures into python :D
– user3471881
Nov 22 at 15:32




We can't copy/paste pictures into python :D
– user3471881
Nov 22 at 15:32




1




1




Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
– maow
Nov 22 at 15:38






Did you try pd.merge([df1, df2], how = 'inner', on = ['year', 'week']?
– maow
Nov 22 at 15:38














1 Answer
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0
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Eventually i solved with with removing the multiindex and doing a good old inner join on the two columns and then recreating the multiindex at the end.
Here are the sniplets:



df=df.reset_index()



df2=df2.reset_index()



df['year']=df['year'].apply(int)



df2['year']=df2['year'].apply(int)



df['week']=df['week'].apply(int)



df2['week']=df2['week'].apply(int)



result = pd.merge(df, df2, how='left', left_on= ['year','week'],right_on= ['year','week'])



result=result.set_index(['year', 'month','week','day'])






share|improve this answer























  • Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
    – leoburgy
    Nov 22 at 16:08











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1 Answer
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active

oldest

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1 Answer
1






active

oldest

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oldest

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active

oldest

votes








up vote
0
down vote













Eventually i solved with with removing the multiindex and doing a good old inner join on the two columns and then recreating the multiindex at the end.
Here are the sniplets:



df=df.reset_index()



df2=df2.reset_index()



df['year']=df['year'].apply(int)



df2['year']=df2['year'].apply(int)



df['week']=df['week'].apply(int)



df2['week']=df2['week'].apply(int)



result = pd.merge(df, df2, how='left', left_on= ['year','week'],right_on= ['year','week'])



result=result.set_index(['year', 'month','week','day'])






share|improve this answer























  • Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
    – leoburgy
    Nov 22 at 16:08















up vote
0
down vote













Eventually i solved with with removing the multiindex and doing a good old inner join on the two columns and then recreating the multiindex at the end.
Here are the sniplets:



df=df.reset_index()



df2=df2.reset_index()



df['year']=df['year'].apply(int)



df2['year']=df2['year'].apply(int)



df['week']=df['week'].apply(int)



df2['week']=df2['week'].apply(int)



result = pd.merge(df, df2, how='left', left_on= ['year','week'],right_on= ['year','week'])



result=result.set_index(['year', 'month','week','day'])






share|improve this answer























  • Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
    – leoburgy
    Nov 22 at 16:08













up vote
0
down vote










up vote
0
down vote









Eventually i solved with with removing the multiindex and doing a good old inner join on the two columns and then recreating the multiindex at the end.
Here are the sniplets:



df=df.reset_index()



df2=df2.reset_index()



df['year']=df['year'].apply(int)



df2['year']=df2['year'].apply(int)



df['week']=df['week'].apply(int)



df2['week']=df2['week'].apply(int)



result = pd.merge(df, df2, how='left', left_on= ['year','week'],right_on= ['year','week'])



result=result.set_index(['year', 'month','week','day'])






share|improve this answer














Eventually i solved with with removing the multiindex and doing a good old inner join on the two columns and then recreating the multiindex at the end.
Here are the sniplets:



df=df.reset_index()



df2=df2.reset_index()



df['year']=df['year'].apply(int)



df2['year']=df2['year'].apply(int)



df['week']=df['week'].apply(int)



df2['week']=df2['week'].apply(int)



result = pd.merge(df, df2, how='left', left_on= ['year','week'],right_on= ['year','week'])



result=result.set_index(['year', 'month','week','day'])







share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 22 at 16:20

























answered Nov 22 at 15:51









acronis011

33




33












  • Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
    – leoburgy
    Nov 22 at 16:08


















  • Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
    – leoburgy
    Nov 22 at 16:08
















Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
– leoburgy
Nov 22 at 16:08




Since flattening index is not that intuitive for many, I'd suggest that you could add the actual code that you used, so that others could benefit from your experience ;) stackoverflow.blog/2011/07/01/…
– leoburgy
Nov 22 at 16:08


















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