How to randomly select rows from a data set using pandas?

Question

I have a data set with 36k rows. I want to randomly select 9k rows from it using pandas. How do I accomplish this task?

I am new to stack overflow. I will do it. I have clicked on up arrow. i hope u received the upvote :-) — Niranjan Agnihotri, Mar 28 '17 at 07:42
Really a dupe of this:http://stackoverflow.com/questions/15923826/random-row-selection-in-pandas-dataframe see last answer — EdChum, Mar 28 '17 at 08:01

jezrael · Accepted Answer · 2017-03-28T07:24:51.857

14

I think you can use sample - 9k or 25% rows:

df.sample(n=9000)

Or:

df.sample(frac=0.25)

Another solution with creating random sample of index by numpy.random.choice and then select by loc - index has to be unique:

df = df.loc[np.random.choice(df.index, size=9000)]

Solution if not unique index:

df = df.iloc[np.random.choice(np.arange(len(df)), size=9000)]

edited Mar 28 '17 at 07:24

answered Mar 28 '17 at 06:58

jezrael

score 7 · Answer 2 · answered Mar 28 '17 at 07:10

7

numpy

i = np.random.permutation(np.arange(len(df)))
idx = i[:9000]
pd.DataFrame(df.values[idx], df.index[idx])

answered Mar 28 '17 at 07:10

piRSquared

2 Answers2