I have arrays
a = numpy.array([1,3,5,7])
b = pandas.Series([1,2,3,4,5,6,7,8,9])
Is there a quick command to find all of the matching indices in b that contain a value in a? For example
a in b = [0,2,4,6]
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2 Answers
You can use isin to find where values exist in an array-like object (also works for list):
In [14]:
a = np.array([1,3,5,7])
b = pd.Series([1,2,3,4,5,6,7,8,9])
# call .index if you are just interested in the index values
b[b.isin(a)].index
Out[14]:
Int64Index([0, 2, 4, 6], dtype='int64')
Without accessing the .index attribute you get a series returned:
In [15]:
b[b.isin(a)]
Out[15]:
0 1
2 3
4 5
6 7
dtype: int64
