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python-3.xpandasseries

pandas series || get index of string if present

Please bear with me. I am new to pandas and using series within it.

import pandas as pd

s = pd.Series(["koala", "dog", "chameleon"])

'dog' in s.values - this allows test if it is present or otherwise.

s.isin(['dog']).any() - this works true. But there isn't any way to get index or use find.

How do I find index/location of "dog"?

Second, if I have duplicate entries (of dog, for e.g.):

s = pd.Series(["koala", "dog", "chameleon","dog"])

How would I be able to find first or last occurrence?

I am on python 3X (OS X, M1):
Python 3.9.8 (v3.9.8:bb3fdcfe95, Nov 5 2021, 16:40:46) [Clang 13.0.0 (clang-1300.0.29.3)] on darwin

Solution

  • You can use [].index to get the index of a value in a series.

    s = pd.Series(["koala", "dog", "chameleon"])
s[s == 'dog'].index

    Similarly to get the first and last occurrence using min() and max():

    s = pd.Series(["koala", "dog", "chameleon","dog"])
d_first, d_last = s[s == 'dog'].index.min(), s[s == 'dog'].index.max()