Associations nan_replace_value affects original input data

[daanknoors]

Thanks for all the work on this package - it's been really helpful.

I noticed a minor bug. When running associations or compute_associations the nan_replace_strategy affects the original input data. Hence, if you have a dataframe with NaN values in certain columns, these get replaced in the original input. It would be better to work on a copy of the original data, instead of processing the data inplace.

Pandas gives the following warning:

SettingWithCopyWarning: 
A value is trying to be set on a copy of a slice from a DataFrame

[shakedzy]

@daanknoors thanks for this - you're right. I think there's an easy fix for it.

[shakedzy]

Fixed in version 0.6.6

[daanknoors]

Thanks for the quick fix! Tested it and seems to work correctly.