Extending dates for values in a dataframe Python





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I have data that looks like:



Year      Month       Region       Value1       Value2
2016 1 west 2 3
2016 1 east 4 5
2016 1 north 5 3
2016 2 west 6 4
2016 2 east 7 3
.
.
2016 12 west 2 3
2016 12 east 3 7
2016 12 north 6 8
2017 1 west 2 3
.
.
2018 7 west 1 1
2018 7 east 9 9
2018 7 north 5 1


I want to extend my values into Year 2021 for each Month but keep the previous values from the final month in the set (Month 7 of Year 2018).



The desired output would be attached to the ends of each set by Region, Month, and Year like:



2018        7         west         1            1
2018 7 east 9 9
2018 7 north 5 1
2018 8 west 1 1
2018 8 east 9 9
2018 8 north 5 1
2018 9 west 1 1
2018 9 east 9 9
2018 9 north 5 1
.
.
2019 7 west 1 1
2019 7 east 9 9
2019 7 north 5 1
.
.
2021 7 west 1 1
2021 7 east 9 9
2021 7 north 5 1


What would the best way to approach this be?










share|improve this question





























    0















    I have data that looks like:



    Year      Month       Region       Value1       Value2
    2016 1 west 2 3
    2016 1 east 4 5
    2016 1 north 5 3
    2016 2 west 6 4
    2016 2 east 7 3
    .
    .
    2016 12 west 2 3
    2016 12 east 3 7
    2016 12 north 6 8
    2017 1 west 2 3
    .
    .
    2018 7 west 1 1
    2018 7 east 9 9
    2018 7 north 5 1


    I want to extend my values into Year 2021 for each Month but keep the previous values from the final month in the set (Month 7 of Year 2018).



    The desired output would be attached to the ends of each set by Region, Month, and Year like:



    2018        7         west         1            1
    2018 7 east 9 9
    2018 7 north 5 1
    2018 8 west 1 1
    2018 8 east 9 9
    2018 8 north 5 1
    2018 9 west 1 1
    2018 9 east 9 9
    2018 9 north 5 1
    .
    .
    2019 7 west 1 1
    2019 7 east 9 9
    2019 7 north 5 1
    .
    .
    2021 7 west 1 1
    2021 7 east 9 9
    2021 7 north 5 1


    What would the best way to approach this be?










    share|improve this question

























      0












      0








      0


      0






      I have data that looks like:



      Year      Month       Region       Value1       Value2
      2016 1 west 2 3
      2016 1 east 4 5
      2016 1 north 5 3
      2016 2 west 6 4
      2016 2 east 7 3
      .
      .
      2016 12 west 2 3
      2016 12 east 3 7
      2016 12 north 6 8
      2017 1 west 2 3
      .
      .
      2018 7 west 1 1
      2018 7 east 9 9
      2018 7 north 5 1


      I want to extend my values into Year 2021 for each Month but keep the previous values from the final month in the set (Month 7 of Year 2018).



      The desired output would be attached to the ends of each set by Region, Month, and Year like:



      2018        7         west         1            1
      2018 7 east 9 9
      2018 7 north 5 1
      2018 8 west 1 1
      2018 8 east 9 9
      2018 8 north 5 1
      2018 9 west 1 1
      2018 9 east 9 9
      2018 9 north 5 1
      .
      .
      2019 7 west 1 1
      2019 7 east 9 9
      2019 7 north 5 1
      .
      .
      2021 7 west 1 1
      2021 7 east 9 9
      2021 7 north 5 1


      What would the best way to approach this be?










      share|improve this question














      I have data that looks like:



      Year      Month       Region       Value1       Value2
      2016 1 west 2 3
      2016 1 east 4 5
      2016 1 north 5 3
      2016 2 west 6 4
      2016 2 east 7 3
      .
      .
      2016 12 west 2 3
      2016 12 east 3 7
      2016 12 north 6 8
      2017 1 west 2 3
      .
      .
      2018 7 west 1 1
      2018 7 east 9 9
      2018 7 north 5 1


      I want to extend my values into Year 2021 for each Month but keep the previous values from the final month in the set (Month 7 of Year 2018).



      The desired output would be attached to the ends of each set by Region, Month, and Year like:



      2018        7         west         1            1
      2018 7 east 9 9
      2018 7 north 5 1
      2018 8 west 1 1
      2018 8 east 9 9
      2018 8 north 5 1
      2018 9 west 1 1
      2018 9 east 9 9
      2018 9 north 5 1
      .
      .
      2019 7 west 1 1
      2019 7 east 9 9
      2019 7 north 5 1
      .
      .
      2021 7 west 1 1
      2021 7 east 9 9
      2021 7 north 5 1


      What would the best way to approach this be?







      python python-3.x pandas python-2.7 dataframe






      share|improve this question













      share|improve this question











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      share|improve this question










      asked Nov 21 '18 at 23:23









      HelloToEarthHelloToEarth

      532215




      532215
























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          1














          I would create a function that uses pd.date_range with a freq of months:



          This functions assumes that you have three regions but can be modified for more.



          def myFunction(df, periods, freq='M'):
          # find the last date in the df
          last = pd.to_datetime(df.Year*10000+df.Month*100+1,format='%Y%m%d').max()

          # create new date range based on n periods with a freq of months
          newDates = pd.date_range(start=last, periods=periods+1, freq=freq)
          newDates = newDates[newDates>last]
          newDates = newDates[:periods+1]
          new_df = pd.DataFrame({'Date':newDates})[1:]

          # convert Date to year and month columns
          new_df['Year'] = new_df['Date'].dt.year
          new_df['Month'] = new_df['Date'].dt.month
          new_df.drop(columns='Date', inplace=True)

          # add your three regions and ffill values
          west = df[:-2].append([new_df], sort=False, ignore_index=True).ffill()
          east = df[:-1].append([new_df], sort=False, ignore_index=True).ffill()
          north = df.append([new_df], sort=False, ignore_index=True).ffill()

          # append you three region dfs and drop duplicates
          new = west.append([east,north], sort=False, ignore_index=True).drop_duplicates()
          return new.sort_values(['Year', 'Month']).reset_index().drop(columns='index')

          myFunction(df,3)


          with periods set to three this will return the next three months...



              Year    Month   Region  Value1  Value2
          0 2016 1 west 2.0 3.0
          1 2016 1 east 4.0 5.0
          2 2016 1 north 5.0 3.0
          3 2016 2 west 6.0 4.0
          4 2016 2 east 7.0 3.0
          5 2016 12 west 2.0 3.0
          6 2016 12 east 3.0 7.0
          7 2016 12 north 6.0 8.0
          8 2017 1 west 2.0 3.0
          9 2018 7 west 1.0 1.0
          10 2018 7 east 9.0 9.0
          11 2018 7 north 5.0 1.0
          12 2018 8 west 1.0 1.0
          13 2018 8 east 9.0 9.0
          14 2018 8 north 5.0 1.0
          15 2018 9 west 1.0 1.0
          16 2018 9 east 9.0 9.0
          17 2018 9 north 5.0 1.0
          18 2018 10 west 1.0 1.0
          19 2018 10 east 9.0 9.0
          20 2018 10 north 5.0 1.0





          share|improve this answer
























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            1 Answer
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            1














            I would create a function that uses pd.date_range with a freq of months:



            This functions assumes that you have three regions but can be modified for more.



            def myFunction(df, periods, freq='M'):
            # find the last date in the df
            last = pd.to_datetime(df.Year*10000+df.Month*100+1,format='%Y%m%d').max()

            # create new date range based on n periods with a freq of months
            newDates = pd.date_range(start=last, periods=periods+1, freq=freq)
            newDates = newDates[newDates>last]
            newDates = newDates[:periods+1]
            new_df = pd.DataFrame({'Date':newDates})[1:]

            # convert Date to year and month columns
            new_df['Year'] = new_df['Date'].dt.year
            new_df['Month'] = new_df['Date'].dt.month
            new_df.drop(columns='Date', inplace=True)

            # add your three regions and ffill values
            west = df[:-2].append([new_df], sort=False, ignore_index=True).ffill()
            east = df[:-1].append([new_df], sort=False, ignore_index=True).ffill()
            north = df.append([new_df], sort=False, ignore_index=True).ffill()

            # append you three region dfs and drop duplicates
            new = west.append([east,north], sort=False, ignore_index=True).drop_duplicates()
            return new.sort_values(['Year', 'Month']).reset_index().drop(columns='index')

            myFunction(df,3)


            with periods set to three this will return the next three months...



                Year    Month   Region  Value1  Value2
            0 2016 1 west 2.0 3.0
            1 2016 1 east 4.0 5.0
            2 2016 1 north 5.0 3.0
            3 2016 2 west 6.0 4.0
            4 2016 2 east 7.0 3.0
            5 2016 12 west 2.0 3.0
            6 2016 12 east 3.0 7.0
            7 2016 12 north 6.0 8.0
            8 2017 1 west 2.0 3.0
            9 2018 7 west 1.0 1.0
            10 2018 7 east 9.0 9.0
            11 2018 7 north 5.0 1.0
            12 2018 8 west 1.0 1.0
            13 2018 8 east 9.0 9.0
            14 2018 8 north 5.0 1.0
            15 2018 9 west 1.0 1.0
            16 2018 9 east 9.0 9.0
            17 2018 9 north 5.0 1.0
            18 2018 10 west 1.0 1.0
            19 2018 10 east 9.0 9.0
            20 2018 10 north 5.0 1.0





            share|improve this answer




























              1














              I would create a function that uses pd.date_range with a freq of months:



              This functions assumes that you have three regions but can be modified for more.



              def myFunction(df, periods, freq='M'):
              # find the last date in the df
              last = pd.to_datetime(df.Year*10000+df.Month*100+1,format='%Y%m%d').max()

              # create new date range based on n periods with a freq of months
              newDates = pd.date_range(start=last, periods=periods+1, freq=freq)
              newDates = newDates[newDates>last]
              newDates = newDates[:periods+1]
              new_df = pd.DataFrame({'Date':newDates})[1:]

              # convert Date to year and month columns
              new_df['Year'] = new_df['Date'].dt.year
              new_df['Month'] = new_df['Date'].dt.month
              new_df.drop(columns='Date', inplace=True)

              # add your three regions and ffill values
              west = df[:-2].append([new_df], sort=False, ignore_index=True).ffill()
              east = df[:-1].append([new_df], sort=False, ignore_index=True).ffill()
              north = df.append([new_df], sort=False, ignore_index=True).ffill()

              # append you three region dfs and drop duplicates
              new = west.append([east,north], sort=False, ignore_index=True).drop_duplicates()
              return new.sort_values(['Year', 'Month']).reset_index().drop(columns='index')

              myFunction(df,3)


              with periods set to three this will return the next three months...



                  Year    Month   Region  Value1  Value2
              0 2016 1 west 2.0 3.0
              1 2016 1 east 4.0 5.0
              2 2016 1 north 5.0 3.0
              3 2016 2 west 6.0 4.0
              4 2016 2 east 7.0 3.0
              5 2016 12 west 2.0 3.0
              6 2016 12 east 3.0 7.0
              7 2016 12 north 6.0 8.0
              8 2017 1 west 2.0 3.0
              9 2018 7 west 1.0 1.0
              10 2018 7 east 9.0 9.0
              11 2018 7 north 5.0 1.0
              12 2018 8 west 1.0 1.0
              13 2018 8 east 9.0 9.0
              14 2018 8 north 5.0 1.0
              15 2018 9 west 1.0 1.0
              16 2018 9 east 9.0 9.0
              17 2018 9 north 5.0 1.0
              18 2018 10 west 1.0 1.0
              19 2018 10 east 9.0 9.0
              20 2018 10 north 5.0 1.0





              share|improve this answer


























                1












                1








                1







                I would create a function that uses pd.date_range with a freq of months:



                This functions assumes that you have three regions but can be modified for more.



                def myFunction(df, periods, freq='M'):
                # find the last date in the df
                last = pd.to_datetime(df.Year*10000+df.Month*100+1,format='%Y%m%d').max()

                # create new date range based on n periods with a freq of months
                newDates = pd.date_range(start=last, periods=periods+1, freq=freq)
                newDates = newDates[newDates>last]
                newDates = newDates[:periods+1]
                new_df = pd.DataFrame({'Date':newDates})[1:]

                # convert Date to year and month columns
                new_df['Year'] = new_df['Date'].dt.year
                new_df['Month'] = new_df['Date'].dt.month
                new_df.drop(columns='Date', inplace=True)

                # add your three regions and ffill values
                west = df[:-2].append([new_df], sort=False, ignore_index=True).ffill()
                east = df[:-1].append([new_df], sort=False, ignore_index=True).ffill()
                north = df.append([new_df], sort=False, ignore_index=True).ffill()

                # append you three region dfs and drop duplicates
                new = west.append([east,north], sort=False, ignore_index=True).drop_duplicates()
                return new.sort_values(['Year', 'Month']).reset_index().drop(columns='index')

                myFunction(df,3)


                with periods set to three this will return the next three months...



                    Year    Month   Region  Value1  Value2
                0 2016 1 west 2.0 3.0
                1 2016 1 east 4.0 5.0
                2 2016 1 north 5.0 3.0
                3 2016 2 west 6.0 4.0
                4 2016 2 east 7.0 3.0
                5 2016 12 west 2.0 3.0
                6 2016 12 east 3.0 7.0
                7 2016 12 north 6.0 8.0
                8 2017 1 west 2.0 3.0
                9 2018 7 west 1.0 1.0
                10 2018 7 east 9.0 9.0
                11 2018 7 north 5.0 1.0
                12 2018 8 west 1.0 1.0
                13 2018 8 east 9.0 9.0
                14 2018 8 north 5.0 1.0
                15 2018 9 west 1.0 1.0
                16 2018 9 east 9.0 9.0
                17 2018 9 north 5.0 1.0
                18 2018 10 west 1.0 1.0
                19 2018 10 east 9.0 9.0
                20 2018 10 north 5.0 1.0





                share|improve this answer













                I would create a function that uses pd.date_range with a freq of months:



                This functions assumes that you have three regions but can be modified for more.



                def myFunction(df, periods, freq='M'):
                # find the last date in the df
                last = pd.to_datetime(df.Year*10000+df.Month*100+1,format='%Y%m%d').max()

                # create new date range based on n periods with a freq of months
                newDates = pd.date_range(start=last, periods=periods+1, freq=freq)
                newDates = newDates[newDates>last]
                newDates = newDates[:periods+1]
                new_df = pd.DataFrame({'Date':newDates})[1:]

                # convert Date to year and month columns
                new_df['Year'] = new_df['Date'].dt.year
                new_df['Month'] = new_df['Date'].dt.month
                new_df.drop(columns='Date', inplace=True)

                # add your three regions and ffill values
                west = df[:-2].append([new_df], sort=False, ignore_index=True).ffill()
                east = df[:-1].append([new_df], sort=False, ignore_index=True).ffill()
                north = df.append([new_df], sort=False, ignore_index=True).ffill()

                # append you three region dfs and drop duplicates
                new = west.append([east,north], sort=False, ignore_index=True).drop_duplicates()
                return new.sort_values(['Year', 'Month']).reset_index().drop(columns='index')

                myFunction(df,3)


                with periods set to three this will return the next three months...



                    Year    Month   Region  Value1  Value2
                0 2016 1 west 2.0 3.0
                1 2016 1 east 4.0 5.0
                2 2016 1 north 5.0 3.0
                3 2016 2 west 6.0 4.0
                4 2016 2 east 7.0 3.0
                5 2016 12 west 2.0 3.0
                6 2016 12 east 3.0 7.0
                7 2016 12 north 6.0 8.0
                8 2017 1 west 2.0 3.0
                9 2018 7 west 1.0 1.0
                10 2018 7 east 9.0 9.0
                11 2018 7 north 5.0 1.0
                12 2018 8 west 1.0 1.0
                13 2018 8 east 9.0 9.0
                14 2018 8 north 5.0 1.0
                15 2018 9 west 1.0 1.0
                16 2018 9 east 9.0 9.0
                17 2018 9 north 5.0 1.0
                18 2018 10 west 1.0 1.0
                19 2018 10 east 9.0 9.0
                20 2018 10 north 5.0 1.0






                share|improve this answer












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                share|improve this answer










                answered Nov 22 '18 at 3:19









                ChrisChris

                3,2082523




                3,2082523
































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