Pandas boolean algebra: True if True in both columns

Question

I would like to make a boolean vector that is created by the comparison of two input boolean vectors. I can use a for loop, but is there a better way to do this?

My ideal solution would look like this:

df['A'] = [True, False, False, True]
df['B'] = [True, False, False, False]
C = ((df['A']==True) or (df['B']==True)).as_matrix()
print C

>>> True, False, False, True

score 4 · Accepted Answer · answered Jan 04 '16 at 20:10

4

I think this is what you are looking for:

C = (df['A']) | (df['B'])
C

0     True
1    False
2    False
3     True
dtype: bool

You could then leave this as a series or convert it to a list or array

answered Jan 04 '16 at 20:10

johnchase

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Got it! The link goes deeper into your solution: http://stackoverflow.com/questions/3845018/python-boolean-operators-vs-bitwise-operators – user3155053 Jan 04 '16 at 20:19

score 4 · Answer 2 · answered Jan 04 '16 at 22:45

Alternatively you could use any method with axis=1 to search in index. It also will work for any number of columns where you have True values:

In [1105]: df
Out[1105]: 
       B      A
0   True   True
1  False  False
2  False  False
3  False   True

In [1106]: df.any(axis=1)
Out[1106]: 
0     True
1    False
2    False
3     True
dtype: bool

Pandas boolean algebra: True if True in both columns

2 Answers2