Remove rows not isin X

Question

Sorry just getting into Pandas  this seems like it should be a very straight forward question  How can I use the isin  X   to remove rows that are in the list X  In R I would write  which a  in  b

User · Answer

You have many options  Collating some of the answers above and the accepted answer from this post you can do  1  df -df  column   isin   value     2  df  df  column   isin   value     3  df df  column   isin   value       False  4  df np logical not df  column   isin   value       Note  for option 4 for you ll need to import numpy as np  Update  You can also use the  query method for this too  This allows for method chaining  5   df query  column not in  values    where values is a list of the values that you don t want to include

User · Answer

You can use numpy logical not to invert the boolean array returned by isin   In  63   s   pd Series np arange 10 0    In  64   x   range 4  8   In  65   mask   np logical not s isin x    In  66   s mask  Out 66    0    0 1    1 2    2 3    3 8    8 9    9   As given in the comment by Wes McKinney you can also use  s  s isin x

User · Answer

All you have to do is create a subset of your dataframe where the isin method evaluates to False   df   df df  Column Name   isin   Value       False

User · Answer

You can use the DataFrame select method   In  1   df   pd DataFrame   1 2   3 4    index   A   B     In  2   df Out 2       0  1 A  1  2 B  3  4  In  3   L     A    In  4   df select lambda x  x in L  Out 4       0  1 A  1  2

[python] Remove rows not .isin('X')

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