drop a series of true false in pandas removes first two lines

Question

Handing the pandas.drop function a list of True and False statements drops the first two lines. Why? Is this a bug?

df = pd.DataFrame({         


        

Answer 1

Explanation why this happens

No, this is not a bug, it is just a side-effect of that True and False are equal to 1 and 0

This code:

df = pd.DataFrame({"foo":[1,2,3]})
df.drop([False, False, True])

Is identical to this code:

df = pd.DataFrame({"foo":[1,2,3]})
df.drop([0, 0, 1])

The pandas drop function takes a list of indicies to drop, not a mask.

How to properly use the drop method

The proper way of using masks to drop data is either to mask, then access the index and hand this to the drop function:

df.drop(df[[False, False, True]].index)
   foo
0    1
1    2

Or just by inverted masking:

df[~pd.Series([False, False, True])]
   foo
0    1
1    2