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pythonpython-3.xfunctionhigher-order-functionsfunction-parameter

Passing Function as parameter in python


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.


Solution

  • 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')