“Drop random rows” from pandas dataframe

Question

In a pandas dataframe, how can I drop a random subset of rows that obey a condition?

In other words, if I have a Pandas dataframe w

Answer 1

Use the frac argument

df.sample(frac=.5)

If you define the amount you want to drop in a variable n

n = .5
df.sample(frac=1 - n)

To include the condition, use drop

df.drop(df.query('Label == 1').sample(frac=.5).index)

   Label   A
0      0   1
1      0   2
2      0   3
4      1  11
6      1  13