group data using pandas, but how do I keep the order of the group and do math on two of the columns rows?





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df:



    Time Name  X  Y
0 00 AA 0 0
1 30 BB 1 1
2 45 CC 2 2
3 60 GG:AB 3 3
4 90 GG:AC 4 4
5 120 AA 5 3


dataGroup = df.groupby



([pd.Grouper(key=Time,freq='30s'),'Name'])).sort_values(by=['Timestamp'],ascending=True)


I have tried doing a diff() on the row, but it is returning NaN or something not expected.



df.groupby('Name', sort=False)['X'].diff()


How do I keep the groupings and the time sort, and do diff between a row and its previous row (for both the X and the Y column)



Expected output:
XDiff would be Group AA,
XDiff row 1 = (X row1 - origin (known))
XDiff row 2 = (X row2 - X row1)



    Time Name  X  Y XDiff  YDiff
0 00 AA 0 0 0 0
5 120 AA 5 3 5 3
1 30 BB 1 1 0 0
6 55 BB 2 3 1 2
2 45 CC 2 2 0 0
3 60 GG:AB 3 3 0 0
4 90 GG:AC 4 4 0 0


It would be nice to see the total distance for each group (ie, AA is 5, BB is 1)
In my example, I only have a couple of rows for each group, but what if there were 100 of them, the diff would give me values for the distance between any two, but not the total distance for that group.










share|improve this question

























  • Can you post the expected output?

    – harvpan
    Nov 16 '18 at 16:07











  • related / possible duplicate: stackoverflow.com/questions/20648346/…

    – Evan
    Nov 16 '18 at 16:41











  • Can you clarify what you mean by "total distance"?

    – Evan
    Nov 16 '18 at 16:53











  • Possible duplicate of Computing diffs within groups of a dataframe

    – Evan
    Nov 16 '18 at 16:53


















0















df:



    Time Name  X  Y
0 00 AA 0 0
1 30 BB 1 1
2 45 CC 2 2
3 60 GG:AB 3 3
4 90 GG:AC 4 4
5 120 AA 5 3


dataGroup = df.groupby



([pd.Grouper(key=Time,freq='30s'),'Name'])).sort_values(by=['Timestamp'],ascending=True)


I have tried doing a diff() on the row, but it is returning NaN or something not expected.



df.groupby('Name', sort=False)['X'].diff()


How do I keep the groupings and the time sort, and do diff between a row and its previous row (for both the X and the Y column)



Expected output:
XDiff would be Group AA,
XDiff row 1 = (X row1 - origin (known))
XDiff row 2 = (X row2 - X row1)



    Time Name  X  Y XDiff  YDiff
0 00 AA 0 0 0 0
5 120 AA 5 3 5 3
1 30 BB 1 1 0 0
6 55 BB 2 3 1 2
2 45 CC 2 2 0 0
3 60 GG:AB 3 3 0 0
4 90 GG:AC 4 4 0 0


It would be nice to see the total distance for each group (ie, AA is 5, BB is 1)
In my example, I only have a couple of rows for each group, but what if there were 100 of them, the diff would give me values for the distance between any two, but not the total distance for that group.










share|improve this question

























  • Can you post the expected output?

    – harvpan
    Nov 16 '18 at 16:07











  • related / possible duplicate: stackoverflow.com/questions/20648346/…

    – Evan
    Nov 16 '18 at 16:41











  • Can you clarify what you mean by "total distance"?

    – Evan
    Nov 16 '18 at 16:53











  • Possible duplicate of Computing diffs within groups of a dataframe

    – Evan
    Nov 16 '18 at 16:53














0












0








0








df:



    Time Name  X  Y
0 00 AA 0 0
1 30 BB 1 1
2 45 CC 2 2
3 60 GG:AB 3 3
4 90 GG:AC 4 4
5 120 AA 5 3


dataGroup = df.groupby



([pd.Grouper(key=Time,freq='30s'),'Name'])).sort_values(by=['Timestamp'],ascending=True)


I have tried doing a diff() on the row, but it is returning NaN or something not expected.



df.groupby('Name', sort=False)['X'].diff()


How do I keep the groupings and the time sort, and do diff between a row and its previous row (for both the X and the Y column)



Expected output:
XDiff would be Group AA,
XDiff row 1 = (X row1 - origin (known))
XDiff row 2 = (X row2 - X row1)



    Time Name  X  Y XDiff  YDiff
0 00 AA 0 0 0 0
5 120 AA 5 3 5 3
1 30 BB 1 1 0 0
6 55 BB 2 3 1 2
2 45 CC 2 2 0 0
3 60 GG:AB 3 3 0 0
4 90 GG:AC 4 4 0 0


It would be nice to see the total distance for each group (ie, AA is 5, BB is 1)
In my example, I only have a couple of rows for each group, but what if there were 100 of them, the diff would give me values for the distance between any two, but not the total distance for that group.










share|improve this question
















df:



    Time Name  X  Y
0 00 AA 0 0
1 30 BB 1 1
2 45 CC 2 2
3 60 GG:AB 3 3
4 90 GG:AC 4 4
5 120 AA 5 3


dataGroup = df.groupby



([pd.Grouper(key=Time,freq='30s'),'Name'])).sort_values(by=['Timestamp'],ascending=True)


I have tried doing a diff() on the row, but it is returning NaN or something not expected.



df.groupby('Name', sort=False)['X'].diff()


How do I keep the groupings and the time sort, and do diff between a row and its previous row (for both the X and the Y column)



Expected output:
XDiff would be Group AA,
XDiff row 1 = (X row1 - origin (known))
XDiff row 2 = (X row2 - X row1)



    Time Name  X  Y XDiff  YDiff
0 00 AA 0 0 0 0
5 120 AA 5 3 5 3
1 30 BB 1 1 0 0
6 55 BB 2 3 1 2
2 45 CC 2 2 0 0
3 60 GG:AB 3 3 0 0
4 90 GG:AC 4 4 0 0


It would be nice to see the total distance for each group (ie, AA is 5, BB is 1)
In my example, I only have a couple of rows for each group, but what if there were 100 of them, the diff would give me values for the distance between any two, but not the total distance for that group.







pandas dataframe pandas-groupby






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edited Nov 16 '18 at 22:13







wegunterjr

















asked Nov 16 '18 at 15:11









wegunterjrwegunterjr

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  • Can you post the expected output?

    – harvpan
    Nov 16 '18 at 16:07











  • related / possible duplicate: stackoverflow.com/questions/20648346/…

    – Evan
    Nov 16 '18 at 16:41











  • Can you clarify what you mean by "total distance"?

    – Evan
    Nov 16 '18 at 16:53











  • Possible duplicate of Computing diffs within groups of a dataframe

    – Evan
    Nov 16 '18 at 16:53



















  • Can you post the expected output?

    – harvpan
    Nov 16 '18 at 16:07











  • related / possible duplicate: stackoverflow.com/questions/20648346/…

    – Evan
    Nov 16 '18 at 16:41











  • Can you clarify what you mean by "total distance"?

    – Evan
    Nov 16 '18 at 16:53











  • Possible duplicate of Computing diffs within groups of a dataframe

    – Evan
    Nov 16 '18 at 16:53

















Can you post the expected output?

– harvpan
Nov 16 '18 at 16:07





Can you post the expected output?

– harvpan
Nov 16 '18 at 16:07













related / possible duplicate: stackoverflow.com/questions/20648346/…

– Evan
Nov 16 '18 at 16:41





related / possible duplicate: stackoverflow.com/questions/20648346/…

– Evan
Nov 16 '18 at 16:41













Can you clarify what you mean by "total distance"?

– Evan
Nov 16 '18 at 16:53





Can you clarify what you mean by "total distance"?

– Evan
Nov 16 '18 at 16:53













Possible duplicate of Computing diffs within groups of a dataframe

– Evan
Nov 16 '18 at 16:53





Possible duplicate of Computing diffs within groups of a dataframe

– Evan
Nov 16 '18 at 16:53












1 Answer
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oldest

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Ripping off https://stackoverflow.com/a/20664760/6672746, you can use a lambda function to calculate the difference between rows for X and Y. I also included two lines to set the index (after the groupby) and sort it.



df['x_diff'] = df.groupby(['Name'])['X'].transform(lambda x: x.diff()).fillna(0)
df['y_diff'] = df.groupby(['Name'])['Y'].transform(lambda x: x.diff()).fillna(0)
df.set_index(["Name", "Time"], inplace=True)
df.sort_index(level=["Name", "Time"], inplace=True)


Output:



            X  Y  x_diff  y_diff
Name Time
AA 0 0 0 0.0 0.0
120 5 3 5.0 3.0
BB 30 1 1 0.0 0.0
CC 45 2 2 0.0 0.0
GG:AB 60 3 3 0.0 0.0
GG:AC 90 4 4 0.0 0.0





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    1 Answer
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    active

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    Ripping off https://stackoverflow.com/a/20664760/6672746, you can use a lambda function to calculate the difference between rows for X and Y. I also included two lines to set the index (after the groupby) and sort it.



    df['x_diff'] = df.groupby(['Name'])['X'].transform(lambda x: x.diff()).fillna(0)
    df['y_diff'] = df.groupby(['Name'])['Y'].transform(lambda x: x.diff()).fillna(0)
    df.set_index(["Name", "Time"], inplace=True)
    df.sort_index(level=["Name", "Time"], inplace=True)


    Output:



                X  Y  x_diff  y_diff
    Name Time
    AA 0 0 0 0.0 0.0
    120 5 3 5.0 3.0
    BB 30 1 1 0.0 0.0
    CC 45 2 2 0.0 0.0
    GG:AB 60 3 3 0.0 0.0
    GG:AC 90 4 4 0.0 0.0





    share|improve this answer






























      0














      Ripping off https://stackoverflow.com/a/20664760/6672746, you can use a lambda function to calculate the difference between rows for X and Y. I also included two lines to set the index (after the groupby) and sort it.



      df['x_diff'] = df.groupby(['Name'])['X'].transform(lambda x: x.diff()).fillna(0)
      df['y_diff'] = df.groupby(['Name'])['Y'].transform(lambda x: x.diff()).fillna(0)
      df.set_index(["Name", "Time"], inplace=True)
      df.sort_index(level=["Name", "Time"], inplace=True)


      Output:



                  X  Y  x_diff  y_diff
      Name Time
      AA 0 0 0 0.0 0.0
      120 5 3 5.0 3.0
      BB 30 1 1 0.0 0.0
      CC 45 2 2 0.0 0.0
      GG:AB 60 3 3 0.0 0.0
      GG:AC 90 4 4 0.0 0.0





      share|improve this answer




























        0












        0








        0







        Ripping off https://stackoverflow.com/a/20664760/6672746, you can use a lambda function to calculate the difference between rows for X and Y. I also included two lines to set the index (after the groupby) and sort it.



        df['x_diff'] = df.groupby(['Name'])['X'].transform(lambda x: x.diff()).fillna(0)
        df['y_diff'] = df.groupby(['Name'])['Y'].transform(lambda x: x.diff()).fillna(0)
        df.set_index(["Name", "Time"], inplace=True)
        df.sort_index(level=["Name", "Time"], inplace=True)


        Output:



                    X  Y  x_diff  y_diff
        Name Time
        AA 0 0 0 0.0 0.0
        120 5 3 5.0 3.0
        BB 30 1 1 0.0 0.0
        CC 45 2 2 0.0 0.0
        GG:AB 60 3 3 0.0 0.0
        GG:AC 90 4 4 0.0 0.0





        share|improve this answer















        Ripping off https://stackoverflow.com/a/20664760/6672746, you can use a lambda function to calculate the difference between rows for X and Y. I also included two lines to set the index (after the groupby) and sort it.



        df['x_diff'] = df.groupby(['Name'])['X'].transform(lambda x: x.diff()).fillna(0)
        df['y_diff'] = df.groupby(['Name'])['Y'].transform(lambda x: x.diff()).fillna(0)
        df.set_index(["Name", "Time"], inplace=True)
        df.sort_index(level=["Name", "Time"], inplace=True)


        Output:



                    X  Y  x_diff  y_diff
        Name Time
        AA 0 0 0 0.0 0.0
        120 5 3 5.0 3.0
        BB 30 1 1 0.0 0.0
        CC 45 2 2 0.0 0.0
        GG:AB 60 3 3 0.0 0.0
        GG:AC 90 4 4 0.0 0.0






        share|improve this answer














        share|improve this answer



        share|improve this answer








        edited Nov 16 '18 at 16:49

























        answered Nov 16 '18 at 16:43









        EvanEvan

        1,161516




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