CODEWITHSUNDEEP
pythonpandas
piRSquared
piRSquared

Reputation: 294258

pandas series cumulative argmax

What is an efficient way to get a series of the cumulative argmax of another series?

The way I figured is

import pandas as pd

def cumargmax(series):
    return pd.expanding_apply(series, lambda x: x.argmax())

This works, but I'm wondering if there is a more appropriate way.

Upvotes: 0

Views: 323

Answers (1)

nitin
nitin

Reputation: 7358

You don't need cumargmax function. Instead, you could do this in one line,

pd.expanding_apply(series, lambda x: x.argmax())

pandas 0.18 is deprecating expanding_apply() module level funtions. They are replacing with the following method call, 

series.expanding().apply(lambda x: x.argmax())

Check out documentation at http://pandas.pydata.org/pandas-docs/stable/computation.html

Upvotes: 1

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