I have a pandas Series
object containing boolean values. How can I get a series containing the logical NOT
of each value?
For example, consider a series containing:
True
True
True
False
The series I'd like to get would contain:
False
False
False
True
This seems like it should be reasonably simple, but apparently I've misplaced my mojo =(
To invert a boolean Series, use ~s
:
In [7]: s = pd.Series([True, True, False, True])
In [8]: ~s
Out[8]:
0 False
1 False
2 True
3 False
dtype: bool
Using Python2.7, NumPy 1.8.0, Pandas 0.13.1:
In [119]: s = pd.Series([True, True, False, True]*10000)
In [10]: %timeit np.invert(s)
10000 loops, best of 3: 91.8 µs per loop
In [11]: %timeit ~s
10000 loops, best of 3: 73.5 µs per loop
In [12]: %timeit (-s)
10000 loops, best of 3: 73.5 µs per loop
As of Pandas 0.13.0, Series are no longer subclasses of numpy.ndarray
; they are now subclasses of pd.NDFrame
. This might have something to do with why np.invert(s)
is no longer as fast as ~s
or -s
.
Caveat: timeit
results may vary depending on many factors including hardware, compiler, OS, Python, NumPy and Pandas versions.