CODEWITHSUNDEEP
pythonpandas
Michael Eisenberger
Michael Eisenberger

Reputation: 5

Find values from pandas series in a list and return the index of the match

Is there a way to do this without a loop?

I am thinking about something like this:

pd_series = pd.Series(["c", "d", "a", "b"])
list_map  = ["a", "b", "c", "d"]
In [1]: pd_series.find_in(list_map)
Out [1]: 
0    2
1    3
2    0
3    1

Thanks!

Upvotes: 0

Views: 92

Answers (2)

BENY
BENY

Reputation: 323226

You can using np.vectorize+get_loc

np.vectorize(pd.Index(pd_series).get_loc)(list_map)
Out[499]: array([2, 3, 0, 1])

Upvotes: 1

juanpa.arrivillaga
juanpa.arrivillaga

Reputation: 95873

You could use an actual map instead of a list, assuming the elements are unique:

>>> actual_map = dict(zip(list_map, range(len(list_map))))
>>> actual_map
{'d': 3, 'b': 1, 'a': 0, 'c': 2}
>>> pd_series.map(actual_map)
0    2
1    3
2    0
3    1
dtype: int64

Upvotes: 3

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