Passing Function as parameter in python

Question

I am trying to make a function to calculate rolling mean or sum :

def rolling_lag_creator(dataset,i,func):  
    dataset['Bid']=dataset.loc[:,'Bid'].rolling(window=i).func()
    return dataset

but this function is throwing error when i am calling this:

rolling_lag_creator(Hypothesis_ADS,5,mean)

Error:

NameError: name 'mean' is not defined

while below code works fine:

dataset['Bid']=dataset.loc[:,'Bid'].rolling(window=5).mean()

Can anyone help me how to call such methods as parameters, thank you.

The error message is telling you “name ‘mean’ is not defined’. You need to define the function `mean`. Or refer to an existing function `mean()` — DisappointedByUnaccountableMod, May 25 '20 at 19:39
Rolling function return is rolling object and is not working — Manish Kumar Singh, May 25 '20 at 19:53

score 1 · Accepted Answer · answered May 25 '20 at 19:53

1

mean is a method, not a function per se. And anyway, attribute access doesn't work like that, but you can use getattr, something like this:

def rolling_lag_creator(dataset, i, method_name):
    method = getattr(dataset.loc[:,'Bid'].rolling(window=i), method_name)
    dataset['Bid'] = method()
    return dataset

rolling_lag_creator(Hypothesis_ADS, 5, 'mean')

answered May 25 '20 at 19:53

wjandrea

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Waao , thanks your answer works flawlessly , this is what i needed thank you so much – Manish Kumar Singh May 25 '20 at 20:10

score 0 · Answer 2 · answered May 25 '20 at 19:39

0

I guess you need to:

import numpy as np

and then replace mean with np.mean

answered May 25 '20 at 19:39

Roy2012

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Passing Function as parameter in python

2 Answers2