Random row selection in Pandas dataframe

Question

Is there a way to select random rows from a DataFrame in Pandas  In R  using the car package  there is a useful function some x  n  which is similar to head but selects  in this example  10 rows at random from x  I have also looked at the slicing documentation and there seems to be nothing equivalent  Update Now using version 20  There is a sample method  df sample n

User · Accepted Answer

Something like this   import random  def some x  n       return x ix random sample x index  n     Note  As of Pandas v0 20 0  ix has been deprecated in favour of loc for label based indexing

User · Answer

The best way to do this is with the sample function from the random module   import numpy as np import pandas as pd from random import sample    given data frame df    create random index rindex    np array sample xrange len df    10      get 10 random rows from df dfr   df ix rindex

User · Answer

With pandas version 0 16 1 and up  there is now a DataFrame sample method built-in   import pandas  df   pandas DataFrame pandas np random random 100      Randomly sample 70  of your dataframe df percent   df sample frac 0 7     Randomly sample 7 elements from your dataframe df elements   df sample n 7    For either approach above  you can get the rest of the rows by doing   df rest   df loc  df index isin df percent index

User · Answer

sample  As of v0 20 0  you can use pd DataFrame sample  which can be used to return a random sample of a fixed number rows  or a percentage of rows   df   df sample n k        k rows df   df sample frac k     int len df index    k  rows   For reproducibility  you can specify an integer random state  equivalent to using np ramdom seed  So  instead of setting  for example  np random seed   0  you can   df   df sample n k  random state 0

User · Answer

Below line will randomly select n number of rows out of the total existing row numbers from the dataframe df without replacement   df df take np random permutation len df    n

User · Answer

Actually this will give you repeated indices np random random integers 0  len df   N  where N is a large number

[python] Random row selection in Pandas dataframe

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