Pandas: compare list objects in Series












10















In my dataframe a column is made up of lists, for example:



df = pd.DataFrame({'A':[[1,2],[2,4],[3,1]]})


I need to find out the location of list [1,2] in this dataframe. I tried:



df.loc[df['A'] == [1,2]]


and



df.loc[df['A'] == [[1,2]]]


but failed totally. The comparison seems very simple but that just doesn't work. Am I missing something here?










share|improve this question

























  • The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

    – BallpointBen
    Nov 1 '18 at 21:18











  • @BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

    – Shiang Hoo
    Nov 2 '18 at 9:11













  • @Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

    – jpmc26
    Nov 13 '18 at 22:19













  • Feel free to suggest a more appropriate target.

    – Luuklag
    Nov 13 '18 at 23:05











  • @Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

    – Shiang Hoo
    Nov 19 '18 at 2:56
















10















In my dataframe a column is made up of lists, for example:



df = pd.DataFrame({'A':[[1,2],[2,4],[3,1]]})


I need to find out the location of list [1,2] in this dataframe. I tried:



df.loc[df['A'] == [1,2]]


and



df.loc[df['A'] == [[1,2]]]


but failed totally. The comparison seems very simple but that just doesn't work. Am I missing something here?










share|improve this question

























  • The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

    – BallpointBen
    Nov 1 '18 at 21:18











  • @BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

    – Shiang Hoo
    Nov 2 '18 at 9:11













  • @Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

    – jpmc26
    Nov 13 '18 at 22:19













  • Feel free to suggest a more appropriate target.

    – Luuklag
    Nov 13 '18 at 23:05











  • @Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

    – Shiang Hoo
    Nov 19 '18 at 2:56














10












10








10


2






In my dataframe a column is made up of lists, for example:



df = pd.DataFrame({'A':[[1,2],[2,4],[3,1]]})


I need to find out the location of list [1,2] in this dataframe. I tried:



df.loc[df['A'] == [1,2]]


and



df.loc[df['A'] == [[1,2]]]


but failed totally. The comparison seems very simple but that just doesn't work. Am I missing something here?










share|improve this question
















In my dataframe a column is made up of lists, for example:



df = pd.DataFrame({'A':[[1,2],[2,4],[3,1]]})


I need to find out the location of list [1,2] in this dataframe. I tried:



df.loc[df['A'] == [1,2]]


and



df.loc[df['A'] == [[1,2]]]


but failed totally. The comparison seems very simple but that just doesn't work. Am I missing something here?







python pandas






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 1 '18 at 14:25









Seanny123

2,30743364




2,30743364










asked Nov 1 '18 at 13:53









Shiang HooShiang Hoo

794




794













  • The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

    – BallpointBen
    Nov 1 '18 at 21:18











  • @BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

    – Shiang Hoo
    Nov 2 '18 at 9:11













  • @Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

    – jpmc26
    Nov 13 '18 at 22:19













  • Feel free to suggest a more appropriate target.

    – Luuklag
    Nov 13 '18 at 23:05











  • @Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

    – Shiang Hoo
    Nov 19 '18 at 2:56



















  • The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

    – BallpointBen
    Nov 1 '18 at 21:18











  • @BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

    – Shiang Hoo
    Nov 2 '18 at 9:11













  • @Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

    – jpmc26
    Nov 13 '18 at 22:19













  • Feel free to suggest a more appropriate target.

    – Luuklag
    Nov 13 '18 at 23:05











  • @Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

    – Shiang Hoo
    Nov 19 '18 at 2:56

















The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

– BallpointBen
Nov 1 '18 at 21:18





The only thing you're "missing" is that data frames aren't really great for storing lists. Any reason you don't want two separate columns?

– BallpointBen
Nov 1 '18 at 21:18













@BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

– Shiang Hoo
Nov 2 '18 at 9:11







@BallpointBen Thanks for your attention, I've posted a new question to explain the whole question. stackoverflow.com/questions/53115592/…

– Shiang Hoo
Nov 2 '18 at 9:11















@Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

– jpmc26
Nov 13 '18 at 22:19







@Luuklag This may be a duplicate, but I don't believe it's a duplicate of the target you suggest. That one seems to be trying to filter based on whether multiple columns are equal to particular values. This one is trying to check if the list is equal to a single column's value, which has a very different answer.

– jpmc26
Nov 13 '18 at 22:19















Feel free to suggest a more appropriate target.

– Luuklag
Nov 13 '18 at 23:05





Feel free to suggest a more appropriate target.

– Luuklag
Nov 13 '18 at 23:05













@Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

– Shiang Hoo
Nov 19 '18 at 2:56





@Luuklag, I posted the two questions because I don't think they are the same. As jpmc described, they are connected but also very different. This post is actually the varietas of that one: I tried stupid things to solve that one and based on the stupid thing I posted this one. But this one still has its distinct value. Can you please remove the duplicate target?

– Shiang Hoo
Nov 19 '18 at 2:56












5 Answers
5






active

oldest

votes


















12














Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:



df.A.map(tuple).isin([(1,2)])
Out[293]:
0 True
1 False
2 False
Name: A, dtype: bool
#df[df.A.map(tuple).isin([(1,2)])]





share|improve this answer

































    10














    You can use apply and compare as:



    df['A'].apply(lambda x: x==[1,2])

    0 True
    1 False
    2 False
    Name: A, dtype: bool




    print(df[df['A'].apply(lambda x: x==[1,2])])

    A
    0 [1, 2]





    share|improve this answer































      9














      With Numpy arrays



      df.assign(B=(np.array(df.A.tolist()) == [1, 2]).all(1))

      A B
      0 [1, 2] True
      1 [2, 4] False
      2 [3, 1] False





      share|improve this answer



















      • 2





        This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

        – jpp
        Nov 1 '18 at 14:43











      • Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

        – ALollz
        Nov 1 '18 at 15:40








      • 2





        @ALollz yes and yes

        – piRSquared
        Nov 1 '18 at 15:53











      • Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

        – Shiang Hoo
        Nov 2 '18 at 2:41



















      6














      Using numpy



      df.A.apply(lambda x: (np.array(x) == np.array([1,2])).all())

      0 True
      1 False
      2 False





      share|improve this answer

































        0














        Or:



        df['A'].apply(([1,2]).__eq__)


        Then:



        df[df['A'].apply(([1,2]).__eq__)]





        share|improve this answer























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          5 Answers
          5






          active

          oldest

          votes








          5 Answers
          5






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          12














          Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:



          df.A.map(tuple).isin([(1,2)])
          Out[293]:
          0 True
          1 False
          2 False
          Name: A, dtype: bool
          #df[df.A.map(tuple).isin([(1,2)])]





          share|improve this answer






























            12














            Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:



            df.A.map(tuple).isin([(1,2)])
            Out[293]:
            0 True
            1 False
            2 False
            Name: A, dtype: bool
            #df[df.A.map(tuple).isin([(1,2)])]





            share|improve this answer




























              12












              12








              12







              Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:



              df.A.map(tuple).isin([(1,2)])
              Out[293]:
              0 True
              1 False
              2 False
              Name: A, dtype: bool
              #df[df.A.map(tuple).isin([(1,2)])]





              share|improve this answer















              Do not use list in cell, it creates a lot of problem for pandas. If you do need an object column, using tuple:



              df.A.map(tuple).isin([(1,2)])
              Out[293]:
              0 True
              1 False
              2 False
              Name: A, dtype: bool
              #df[df.A.map(tuple).isin([(1,2)])]






              share|improve this answer














              share|improve this answer



              share|improve this answer








              edited Nov 25 '18 at 19:42









              anothermh

              3,21331531




              3,21331531










              answered Nov 1 '18 at 13:56









              W-BW-B

              104k73165




              104k73165

























                  10














                  You can use apply and compare as:



                  df['A'].apply(lambda x: x==[1,2])

                  0 True
                  1 False
                  2 False
                  Name: A, dtype: bool




                  print(df[df['A'].apply(lambda x: x==[1,2])])

                  A
                  0 [1, 2]





                  share|improve this answer




























                    10














                    You can use apply and compare as:



                    df['A'].apply(lambda x: x==[1,2])

                    0 True
                    1 False
                    2 False
                    Name: A, dtype: bool




                    print(df[df['A'].apply(lambda x: x==[1,2])])

                    A
                    0 [1, 2]





                    share|improve this answer


























                      10












                      10








                      10







                      You can use apply and compare as:



                      df['A'].apply(lambda x: x==[1,2])

                      0 True
                      1 False
                      2 False
                      Name: A, dtype: bool




                      print(df[df['A'].apply(lambda x: x==[1,2])])

                      A
                      0 [1, 2]





                      share|improve this answer













                      You can use apply and compare as:



                      df['A'].apply(lambda x: x==[1,2])

                      0 True
                      1 False
                      2 False
                      Name: A, dtype: bool




                      print(df[df['A'].apply(lambda x: x==[1,2])])

                      A
                      0 [1, 2]






                      share|improve this answer












                      share|improve this answer



                      share|improve this answer










                      answered Nov 1 '18 at 13:56









                      Sandeep KadapaSandeep Kadapa

                      6,277429




                      6,277429























                          9














                          With Numpy arrays



                          df.assign(B=(np.array(df.A.tolist()) == [1, 2]).all(1))

                          A B
                          0 [1, 2] True
                          1 [2, 4] False
                          2 [3, 1] False





                          share|improve this answer



















                          • 2





                            This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                            – jpp
                            Nov 1 '18 at 14:43











                          • Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                            – ALollz
                            Nov 1 '18 at 15:40








                          • 2





                            @ALollz yes and yes

                            – piRSquared
                            Nov 1 '18 at 15:53











                          • Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                            – Shiang Hoo
                            Nov 2 '18 at 2:41
















                          9














                          With Numpy arrays



                          df.assign(B=(np.array(df.A.tolist()) == [1, 2]).all(1))

                          A B
                          0 [1, 2] True
                          1 [2, 4] False
                          2 [3, 1] False





                          share|improve this answer



















                          • 2





                            This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                            – jpp
                            Nov 1 '18 at 14:43











                          • Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                            – ALollz
                            Nov 1 '18 at 15:40








                          • 2





                            @ALollz yes and yes

                            – piRSquared
                            Nov 1 '18 at 15:53











                          • Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                            – Shiang Hoo
                            Nov 2 '18 at 2:41














                          9












                          9








                          9







                          With Numpy arrays



                          df.assign(B=(np.array(df.A.tolist()) == [1, 2]).all(1))

                          A B
                          0 [1, 2] True
                          1 [2, 4] False
                          2 [3, 1] False





                          share|improve this answer













                          With Numpy arrays



                          df.assign(B=(np.array(df.A.tolist()) == [1, 2]).all(1))

                          A B
                          0 [1, 2] True
                          1 [2, 4] False
                          2 [3, 1] False






                          share|improve this answer












                          share|improve this answer



                          share|improve this answer










                          answered Nov 1 '18 at 14:34









                          piRSquaredpiRSquared

                          153k22144287




                          153k22144287








                          • 2





                            This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                            – jpp
                            Nov 1 '18 at 14:43











                          • Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                            – ALollz
                            Nov 1 '18 at 15:40








                          • 2





                            @ALollz yes and yes

                            – piRSquared
                            Nov 1 '18 at 15:53











                          • Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                            – Shiang Hoo
                            Nov 2 '18 at 2:41














                          • 2





                            This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                            – jpp
                            Nov 1 '18 at 14:43











                          • Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                            – ALollz
                            Nov 1 '18 at 15:40








                          • 2





                            @ALollz yes and yes

                            – piRSquared
                            Nov 1 '18 at 15:53











                          • Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                            – Shiang Hoo
                            Nov 2 '18 at 2:41








                          2




                          2





                          This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                          – jpp
                          Nov 1 '18 at 14:43





                          This should be the accepted solution! [Or, if possible, just expanding the series of lists to 2 series.]

                          – jpp
                          Nov 1 '18 at 14:43













                          Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                          – ALollz
                          Nov 1 '18 at 15:40







                          Won't this run into issues if the lists are differently sized, though perhaps that's outside of the scope of this example.

                          – ALollz
                          Nov 1 '18 at 15:40






                          2




                          2





                          @ALollz yes and yes

                          – piRSquared
                          Nov 1 '18 at 15:53





                          @ALollz yes and yes

                          – piRSquared
                          Nov 1 '18 at 15:53













                          Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                          – Shiang Hoo
                          Nov 2 '18 at 2:41





                          Nice! My only concern is, this solution converts datatype twice, what if my dataframe is very big, will this conversion cost more time?

                          – Shiang Hoo
                          Nov 2 '18 at 2:41











                          6














                          Using numpy



                          df.A.apply(lambda x: (np.array(x) == np.array([1,2])).all())

                          0 True
                          1 False
                          2 False





                          share|improve this answer






























                            6














                            Using numpy



                            df.A.apply(lambda x: (np.array(x) == np.array([1,2])).all())

                            0 True
                            1 False
                            2 False





                            share|improve this answer




























                              6












                              6








                              6







                              Using numpy



                              df.A.apply(lambda x: (np.array(x) == np.array([1,2])).all())

                              0 True
                              1 False
                              2 False





                              share|improve this answer















                              Using numpy



                              df.A.apply(lambda x: (np.array(x) == np.array([1,2])).all())

                              0 True
                              1 False
                              2 False






                              share|improve this answer














                              share|improve this answer



                              share|improve this answer








                              edited Nov 21 '18 at 0:28

























                              answered Nov 1 '18 at 14:32









                              VaishaliVaishali

                              18.6k31030




                              18.6k31030























                                  0














                                  Or:



                                  df['A'].apply(([1,2]).__eq__)


                                  Then:



                                  df[df['A'].apply(([1,2]).__eq__)]





                                  share|improve this answer




























                                    0














                                    Or:



                                    df['A'].apply(([1,2]).__eq__)


                                    Then:



                                    df[df['A'].apply(([1,2]).__eq__)]





                                    share|improve this answer


























                                      0












                                      0








                                      0







                                      Or:



                                      df['A'].apply(([1,2]).__eq__)


                                      Then:



                                      df[df['A'].apply(([1,2]).__eq__)]





                                      share|improve this answer













                                      Or:



                                      df['A'].apply(([1,2]).__eq__)


                                      Then:



                                      df[df['A'].apply(([1,2]).__eq__)]






                                      share|improve this answer












                                      share|improve this answer



                                      share|improve this answer










                                      answered Nov 9 '18 at 4:18









                                      U9-ForwardU9-Forward

                                      14k21337




                                      14k21337






























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